Geological Survey Professional Paper 215 Geology of the Southern Guadalupe Mountains, Texas

MIDDLE PART OF GUADALUPE SERIES

Beds of middle Guadalupe age form an assemblage considerably more varied than that of any of the units that preceded them (pl. 7, A). Toward the southeast, they consist of the Cherry Canyon formation, about 1,000 feet thick, which is a succession of fine-grained and generally thin-bedded sandstones, with a number of persistent limestone beds some of which are distinguished as named members. Toward the northwest, the limestone members thicken abruptly and form a continuous succession of limestones, the Goat Seep, which is equivalent to the upper three-fourths of the unit to the south. The lower fourth of the Cherry Canyon formation persists northward as a sandstone tongue a few hundred feet thick. Near the southeast edge of the Goat Seep limestone, the middle Guadalupe beds have a thickness of about 1,500 feet, but farther northwest they dwindle to 750 feet.

In the Delaware Mountains, the middle part of the Guadalupe series, or Cherry Canyon formation, crops out along the crest of the range in a belt 8 or 10 miles wide. Northward, the Cherry Canyon extends along the west face of the Guadalupe Mountains past El Capitan (pl. 3). Farther north, the Goat Seep limestone is extensively exposed along the lower slopes of escarpments and canyon walls that are capped by the younger Capitan and Carlsbad limestones. The Cherry Canyon and Goat Seep formations are exposed also at many places in the downfaulted area west of the high mountains.

FIGURE 6.—Map of western part of area studied, showing distribution of facies and other stratigraphic features in beds of lower Guadalupe age (Brushy canyon formation). (click on image for a PDF version)

CHERRY CANYON FORMATION

The Cherry Canyon formation, as here distinguished, corresponds approximately to that part of the Delaware Mountain group recognized by Beede⁹¹ as consisting of "brownish, rather bituminous shales, with limestones and some sandstones". Its name is taken from Cherry Canyon, which drains eastward across the summit of the Delaware Mountains for about 9 miles, from Pine Spring to a point 3 miles east of the D Ranch Headquarters where it joins Lamar Canyon. The course of Cherry Canyon crosses most of the outcrop of the formation; some parts of the formation near the canyon are covered by Quaternary gravels.

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⁹¹Beede, J. W., Report on the oil and gas possibilities of the University block 46 in Culberson County: Texas Univ. Bull. 2346, p. 13, 1924.

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On the outcrop, the Cherry Canyon formation has a nearly constant thickness of 1,000 feet, but this thickness increases to 1,283 feet in the Niehaus et al., Caldwell No. 1 well, 35 miles east-southeast of El Capitan. In the broad belt along the crest of the Delaware Mountains, it dips at angles of a few degrees to the east-northeast, but toward the west it is considerably broken by strike faults of small displacement. East of the easternmost fault, which crosses the west end of Getaway Gap, the limestone members of the division stand in low, west-facing, frayed-out cuestas, whose eastern, back slopes are cut on the surfaces of resistant beds. The most conspicuous of them is Long Point, capped by limestones of the Manzanita member.

Outcrops of the Cherry Canyon formation are shown on the geologic map, plate 3. Note that to the south, as near section D—D', the belt of outcrop is wide because of the gentle dips and low topographic relief; whereas to the north, as near section B—B', the belt of outcrops is narrow, not because of steeper dips, but because of greater topographic relief. Views of this part of the outcrop, forming smooth slopes between the ledges of the Brushy Canyon formation and the cliffs of the Capitan limestone, are shown in plate 1, plate 5, A, and plate 12.

Sections of the Cherry Canyon formation can be seen on the right-hand half of plate 6. Note that in the area of flat topography to the southeast, only incomplete sections are shown, or complete sections that have been pieced together from measurements in different places, as in sections 37 and 42. In this region, the record of the Niehaus well, also shown on the plate, provides a useful check on the surface measurements. The continuous sections farther to the left (secs. 12-18) are measured on the steep slopes at the south end of the Guadalupe Mountains. For general stratigraphic relations of the formation, see plate 7, A.

SANDSTONE BEDS

The sandstones of the Cherry Canyon formation lie in beds a few inches thick, with occasional thicker layers and layers of hard, platy, shaly sandstone. The thinner beds are all marked by light and dark laminae, possibly varves, of which there are commonly 10 or 20 to the inch; there are occasional zones where they are more closely or more widely spaced. The sand grains are so fine that they cannot ordinarily be distinguished by the unaided eye. A single specimen of the sandstones was examined under the microscope by Ward Smith. It came from beds between the South Wells and Manzanita members at the base of the slope near Pine Spring, and is megascopically similar to the sandstones in other exposures of the formation. It consists of angular grains of quartz and some feldspar, with a maximum diameter of 0.15 millimeter, closely packed in a noncalcareous, argillaceous matrix. There are also a few grains of zircon and tourmaline.

The bedding surfaces in many of the sandstones are straight and smooth, but some are covered by shallow ripple marks, measuring several inches from crest to crest, which trend in a general northeasterly direction (fig. 8). In some exposures, individual beds can be traced for long distances. In others, the bedding is less regular, and the sandstones are cut by channels several feet deep, which are filled by more massive, more shaly, or more calcareous strata than those beneath (fig. 7). The material filling the channels is very irregularly bedded, but almost nowhere contains any conglomerate. Channeling of the sandstones is most common in the lower two-thirds of the formation.

FIGURE 7.—Sections showing channeling and lenticular deposition of sandstones in lower part of Cherry Canyon formation. A and B, in Cherry Canyon, 2 to 3 miles southeast of Frijole Post Office. C and D, in Glover canyon, 2-1/2 miles south of Frijole Post Office.

At some localities the sandstone contains spherical or oval nodules, lenses, and thin beds of fine-grained, gray, sandy limestone or calcareous sandstone, but elsewhere great thicknesses of strata contain no calcareous beds. In some exposures, as on the south side of Getaway Gap, the various rock types appear in rude cyclical order through intervals of 10 or 20 feet of beds. Shaly sandstones below are followed by thin-bedded sandstones, and then by limestone lenses or nodules, after which the succession is repeated (see sec. 40, fig. 5).

LIMESTONE MEMBERS

The limestone beds in most of the Cherry Canyon formation are lenticular, consisting in places of solid limestone members 100 feet or more thick, and in places of thin limestone beds interbedded with thicker layers of sandstone, as shown diagrammatically on plate 7, A. They exhibit considerable variety in lithologic character from place to place. The two members distinguished in the lower part of the formation, the Getaway and South Wells limestones, change in this manner, and between them other thinner, less continuous limestone beds are locally prominent. The upper member of the formation, the Manzanita limestone, is more persistent than the lower members in lithologic character and thickness over wide areas.

The position and extent of the limestone members in this part of the succession has not been described hitherto although various authors have noted the occurrence of limestone interbedded in the sandstones of the Delaware Mountains. The lack of previous observations on the limestone members is partly because the members are poorly developed on the slopes below El Capitan, where most previous stratigraphic sections were measured.

GETAWAY LIMESTONE MEMBER

The Getaway limestone member is a group of limestone beds in the lower part of the Cherry Canyon formation that are widely exposed in the Delaware Mountains (pl. 3). The member caps the rim of the west-facing escarpment of the Delaware Mountains for many miles south of El Capitan, and is the first abundantly fossiliferous layer encountered in the section on passing upward from the Bone Spring limestone.

The member is named for Getaway Gap,⁹² 6 miles Southeast of El Capitan, on whose north and south sides it is well exposed. At the gap, the member has a thickness of 107 feet, and is separated from the uppermost massive sandstones of the Brushy Canyon formation by 192 feet of thin-bedded sandstone (sec. 40, pl. 6).

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⁹²According to Mr. Walter Glover, in the early days of ranching in the country wild horses were frequently rounded up and captured in the basin west of the gap. Now and then, however, they made a dash for freedom, and "got away" through the gap.

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The member is well exposed also along Glover Canyon 2 miles north of the gap (sec. 37a), on the south side of Guadalupe Pass overlooking Guadalupe Canyon (sec. 27), and on the Delaware Mountains escarpment below Guadalupe Summit radio station (sec. 33). At these places, as much as 200 feet of nearly continuous limestone beds is present, but near the middle several layers of sandstone are generally interbedded. In other parts of the area, even at points close to these localities (as shown in fig. 4, A and C), the member thins to 50 feet or less. At some places, as on the slopes below El Capitan (sec. 18, pl. 6), the member nearly disappears, and in the interval where it is expected only a few limestone beds less than a foot thick are present. (Areas in which the member is thin or wanting are shown on fig. 8.)

The Getaway member consists largely of fine-textured black or dark-gray limestone, which weathers to mouse-gray or ashen-gray surfaces. Most of the beds are a few inches to a foot thick, but some parts are thinly laminated or platy. The more granular beds contain small, irregular chert nodules. Many of the bedding surfaces are straight and smooth, but others are nodular, wavy, and hummocky, with straighter-bedded layers deposited over the uneven surface. In exposures 2 to 3 miles east of El Capitan, some of the bedding surfaces are striated and fluted in the same manner as in the black limestones of the Bone Spring. Between some of the limestone beds are thin-bedded or platy sandstone layers and rare partings of marl.

Interbedded with the dark, thin-bedded limestones are some lenses of light-gray, more granular limestone, in places dolomitic, in massive beds 2 to 10 feet thick, which extend 25 to 100 feet along the outcrop. Some of them contain small, rounded limestone pebbles.

The following analyses of limestone from the Getaway limestone member were made:

Analyses, in percent, of limestone from the Getaway limestone member
[Analyses by K. J. Murata; notes on insoluble residues by Charles Milton]

Fossils are abundant in parts of the Getaway limestone member, and include a great diversity of types. They are particularly numerous and well preserved in the granular limestones, where they tend to be concentrated in lenses in the more barren rock. The bivalved shells in such beds are commonly joined together, as though they had not been greatly disturbed after the death of the animal. Some of the fossils are silicified on the weathered surface of the rock, but most of them can be discovered only by breaking the rock. Fusulinids are abundant in the denser limestones, and tend to be oriented in a general northwestward direction (fig. 8), in the same manner as in the sandstones of the underlying Brushy Canyon formation.

Where the limestone beds of the member thin out, their place is taken by platy, shaly sandstones that crop out in ragged ledges. These shaly sandstones contain zones of limestone nodules, which are probably the equivalent of continuous beds elsewhere. In places the nodules appear to be broken and rolled fragments, resulting from the destruction by wave action of a continuous limestone bed, after deposition and before burial.

BEDS ADJACENT TO GETAWAY LIMESTONE MEMBER

In the sandstones that underlie and overlie the Getaway limestone member are occasional limestone beds that are too thin or discontinuous to be mapped or named.

Beneath the Getaway member, in the 100 or 200 feet of beds that separate it from the top of the Brushy Canyon formation, are occasional lenses and channel fillings of clastic or sandy limestone, containing broken fragments of shells. The fossils collected from these beds are referred to below (pp. 41-42) as constituting the sub-Getaway fossil zone.

The interval between the Getaway limestone member and the succeeding South Wells limestone member consists largely of sandstone, but southeast of Getaway Gap a number of thin limestone beds occur (sec. 42, pl. 6). In places they contain fossils, but no collections have been made from them. The limestone beds give place along the outcrop to thin layers of slabby, reddish quartzite, which form resistant ledges that are widely traceable in the field and on aerial photographs. Some of these quartzite ledges are indicated on the geologic map (pl. 3).

SOUTH WELLS LIMESTONE MEMBER

About 200 feet above the Getaway member is another, less prominent, less continuous group of limestone ledges, which is named the South Wells limestone member. The type locality is at the South Wells of the D Ranch, 11 miles southeast of El Capitan (pl. 3).⁹³ The member here consists of several limestone beds as much as 20 feet thick, interbedded with sandstone, and locally replaced by massive sandstone beds.

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⁹³The northern of Beede's two sections includes beds exposed at this locality (op. cit., p. 6).

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In the southeast part of the area, near South Wells, the limestones are gray, fine-grained, and nondolomitic, and form beds a few inches to several feet thick, with some lenses and thin beds of dense, black limestone. The black beds contain numerous well-preserved ammonoids and a few species of brachiopods. The lighter beds have a more diversified brachiopod fauna. In places the limestone beds are replaced laterally by slabby, reddish quartzites. The sandstones beneath some of the limestone ledges are thick-bedded and crop out in bare, rounded slopes.

Farther north, in the southeastern foothills of the Guadalupe Mountains, black limestone beds disappear from the South Wells member. The member here contains beds as much as 10 feet thick of buff, or drab, fine-grained, dolomitic limestone, in part sandy, which weather into large slabs or blocks. Some of these beds contain seams of flat sandstone and limestone pebbles, and in places, irregular segregations of brown chert. Various fossils can be seen in the rock, but they are preserved only as casts or molds. Overlying each massive bed is a few feet of slabby, compact, dolomitic limestone. The limestones are associated with thick beds of brown, calcareous sandstone of a slightly coarser grain than the sandstones above and below. At some places, as in Cherry Canyon 3 miles east of Frijole Post Office, the limestone beds pinch out, and only the thick sandstone beds remain to indicate the position of the member.

The following analysis was made of a specimen of drab dolomitic limestone from the South Wells limestone member collected at the south base of Rader Ridge due north of Nipple Hill:

Analysis of dolomitic limestone from the South Wells limestone member
[Analysis by K. J. Murata; note on insoluble residue by Charles Milton]

MANZANITA LIMESTONE MEMBER

Several hundred feet above the South Wells limestone member, near the top of the Cherry Canyon formation, are the persistent calcareous layers of the Manzanita limestone member (right-hand half of pl. 6). This member is named for Manzanita Spring, three-quarters of a mile east of Frijole Post Office; the type section is on Nipple Hill, a conical butte carved from the member, which rises from the plain near the spring (right-hand end of pl. 4, B). The member crops out as a thin band on the slopes below the limestone cliffs of the Guadalupe Mountains (pl. 9), and extends southward as a broad belt into the Delaware Mountains (pl. 3).

The member has a thickness of 75 to 150 feet, and consists of straight-bedded ledges a few inches to a foot thick, of dense, greenish-gray, earthy limestone, which weather to a striking orange-brown or yellow color. Under the microscope the limestones are seen to contain scattered detrital quartz grains. Some of the layers contain irregular cavities and pockets, part of which are geodes lined with calcite crystals. Some of the geodes were originally the molds of fossil shells. Fossils, however, are all poorly preserved, and none was collected by Fountain or me. Occasionally imprints of ammonoids and crinoid stems can be seen on the bedding surfaces.

The following analyses of limestone from the Manzanita limestone member were made:

Analyses, in percent, of limestone from the Manzanita limestone member
[Analyses by K. J. Murata; notes an insoluble residues by Charles Milton]

The limestone beds are generally separated by partings and thin beds of soft, fine-grained, greenish sandstone. Southeast of Nipple Hill, as near the D Ranch Headquarters in Cherry Canyon, the limestones are divided in the middle by a 50-foot bed of massive, fine-grained, greenish-gray sandstone, which crops out, in rounded ledges. Similar sandstones 50 to 100 feet thick underlie the member.

The most distinctive feature of the Manzanita member is its intercalated beds of altered volcanic ash. These beds appear generally as pale, apple-green siliceous shales or cherts, but in places they are waxy, green, bentonitic clays. The cherts, because of their resistance, are widely distributed in the slope-wash deposits and stream gravels of the region, where they attract notice because of their unusual color. The volcanic ash forms beds as much as 2 feet thick that occur at various positions within the member. The beds are shown by a special symbol on the sections of plate 6.

Ash beds in the Delaware Mountain section, perhaps belonging to the Manzanita member, were noted by Crandall,⁹⁴ who speaks of "some thin layers of a peculiar hard, green argillite * * * 400 to 500 feet below the top of the [Delaware Mountain] formation."

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⁹⁴Crandall, K. H., Permian stratigraphy of southeastern New Mexico and adjacent parts of western Texas: Am, Assoc. Petroleum Geologists Bull., vol. 13, p. 931, 1929.

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Five thin-sections of the ash from different parts of the area have been examined by C. S. Ross of the Geological Survey. He states that ash structures are generally clearly recognizable under the microscope, although somewhat obscured by silicification, as well as by devitrification, which has produced clay minerals and secondary quartz. Some of the softer beds have been so altered to clay minerals that the ash structure, if originally present, is no longer evident.

Analyses, in percent, of bentonitic clay from the Manzanita limestone member
[Analyses by E. T. Erickson]

Specimen localities	SiO2	R2O3 (mostly Al2O3)	MgO	CaO	Na2O	K2O	H2O	Total
1. Side ravine draining into Lamar Canyon from south, 3/4 mile east of bench mark 4923; shows ash structures under microscope	60.88	19.96	2.72	1.34	.78	9.24	4.92	99.84
2. South bank of Cherry Canyon on road leading south from D Ranch headquarters; does not show recognizable ash structures under microscope	51.46	24.84	5.60	1.78	.80	5.02	10.42	99.92

Characteristically, the volcanic ash beds in the Manzanita member are well developed far outside the local outcrop in the southern Guadalupe Mountains; they have been identified in numerous wells drilled in the Delaware Basin area down the dip to the east. They appear, for example, in the Niehaus et al., Caldwell No. 1 well, 35 miles east-southeast of El Capitan, whose log is shown on plate 6. They have been found also in the Getty Oil Co., Dooley No. 7 well in the Getty oil field, east of Carlsbad, N. Mex. (for location see fig. 2), and also in other wells farther east and southeast.

South of Delaware Creek, the orange-brown, straight-bedded limestones of the member change into dark-gray, lumpy limestones containing poorly preserved ammonoids and separated by crumbly greenish marl which contains small limestone lumps. (This facies is separately mapped on pl. 3; see also sec. 42, pl. 6.) The latter beds closely resemble those of the Hegler limestone member of the Bell Canyon formation along the southeast base of the Guadalupe Mountains, as described later in this report. Green chert (volcanic ash) is rare in this facies but was observed in a few places. The lumpy limestones cap many mesas and cuestas in the southeast part of the area, of which the most conspicuous is Long Point. At Long Point (sec. 42), the most prominent part of the member is the lower calcareous division, below the medial sandstone. The upper division is represented by similar beds a few feet thick.

Between Bone and Shirttail Canyons on the west side of the Guadalupe Mountains, the Manzanita member thins out northward and disappears between the Hegler and Capitan limestones above, and the Goat Seep limestone beneath (between secs. 9 and 13, pl. 6).

CHERRY CANYON FORMATION IN AERIAL PHOTOGRAPHS

In aerial photographs, the Cherry Canyon formation is recognized as that belt of outcrop between the prominent sandstone ledges of the Brushy Canyon formation below and to the west, and the top of the Manzanita limestone cuesta above and to the east. As such, it can be traced through the Delaware Mountains for more than 30 miles south of the area studied.

The part below the South Wells member forms a topography of smooth, rounded ridges and hills, minutely dissected by valleys and ravines. Many of the valleys and ravines appear to follow faults or joints, some of which are traceable for many miles from one drainage area to the next. The Getaway limestone member does not make distinctive ledges and is not traceable on the photographs.

In the photographs, the upper part of the formation differs from the lower in having a well-marked cuesta topography, each cuesta consisting of an abrupt west-facing scarp, indented by each stream that drains across it, and of a broad back-slope descending eastward with about the same inclination as the dip of the beds. Two cuestas are more prominent than the rest, a lower westward one corresponding to the South Wells member, and a higher eastward one corresponding to the Manzanita member. The latter may be traced continuously from Long Point southward for nearly 20 miles beyond the area mapped, until it is lost in the faulted area of the southern Delaware Mountains.

SANDSTONE TONGUE OF CHERRY CANYON FORMATION

North of Shirttail Canyon, on the west side of the Guadalupe Mountains, the lower formation of the Delaware Mountain group (Brushy Canyon) is missing by overlap on the Bone Spring limestone, and the upper three-fourths of the succeeding formation (Cherry Canyon) interfingers with the Goat Seep limestone. The lower fourth of the Cherry Canyon formation, however, persists as a layer of sandstone 200 or 300 feet thick. Its outcrop extends northward past Cutoff Mountain into New Mexico, and forms a weak, sandy break in an otherwise continuous succession of limestone.⁹⁵ According to Crandall,⁹⁶ the sandstone pinches out entirely not far to the north in southern New Mexico.

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⁹⁵First described by Baker, C. L., contributions to the stratigraphy of eastern New Mexico: Am. Jour. Sci., 4th ser., vol. 49, p. 114, 1920; later described by Darton, N. H., and Reeside, J. B. Jr., Guadalupe group; Geol. Soc. America Bull., vol. 37, p. 423, 1926, and others. Darton and Reeside ascribed the northward thinning of the Delaware Mountain group entirely to overlap of the lower beds.

⁹⁶Crandall, K. H., op. cit., p. 935.

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For outcrops of the sandstone tongue, see the geologic map, plate 3. The slope on which it is exposed stands out prominently below Shumard Peak and Bush Mountain on the panorama, plate 5, B. The structure of the rocks appearing in a part of this view is shown on section K—K', plate 17. Sections of the sandstone tongue appear on the left-hand third of plate 6, Nos. 1 to 9.

The sandstones are buff or pink, soft, and very fine grained. In the upper part are some interbedded brown, sandy, cherty limestones that contain numerous silicified brachiopods. The sandstone grades into the overlying Goat Seep limestone, and the two types of rock are interbedded at the contact (as in sec. 7, pl. 6).

GOAT SEEP LIMESTONE

DEFINITION

The name Goat Seep limestone is here given to massive or thick-bedded limestones similar to the Capitan limestone, but of pre-Capitan (middle Guadalupe) age, which crop out in the Guadalupe Mountains (pl. 7, A). The name is taken from Goat Seep,⁹⁷ on the west slope of the mountains 1-1/2 miles northwest of Guadalupe Peak (for location, see pls. 3 and 9). The limestones of the formation, in their southeastern, marginal facies, are exposed up the slope from the seep, which issues from sandstones of the underlying Delaware Mountain group. Complete, well-exposed sections of the formation are found on the west-facing escarpment of the Guadalupe Mountains for several miles north of the type locality.

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⁹⁷Shown as "Goat Spring" on the Guadalupe Peak topographic sheet of the Geological Survey, but Goat Seep is the form generally used by the inhabitants of the area.

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In previous reports, the formation has been given various names. Crandall⁹⁸ termed it the "Chupadera limestone," a name imported from the central New Mexico sequence. The unit, however, does not include all of the type † Chupadera, and there is a strong probability that it is younger than any of the † Chupadera. For beds of approximately the same age in Dog Canyon, in the northern Guadalupe Mountains, Lang⁹⁹ proposed the name Dog Canyon limestone, and extended the term to include the beds here called Goat Seep in the southern Guadalupe Mountains. Petroleum geologists, engaged in regional stratigraphic studies, have found the name Dog Canyon confusing because of its similarity to the term Dog Creek shale, used in Oklahoma for beds of about the same age. The term is therefore abandoned, and in this report the name Goat Seep, based on exposures within the area studied, is substituted for it.

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⁹⁸Crandall, K. H., op. cit., p. 933.

⁹⁹Lang, W. B., The Permian formations of the Pecos valley of New Mexico and Texas: Am. Assoc. Petroleum Geologists Bull., vol. 21, p. 858, 1937.

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The true stratigraphic relations of the Goat Seep limestone were clearly recognized by Baker,¹ and later on by Crandall,² but in most of the other reports written at that time it was confused with the similar but younger Capitan limestone. Darton and Reeside³ erroneously identified the Goat Seep beds near the Texas-New Mexico State line as "upper dark limestone" (Pinery limestone member of Bell Canyon formation) and Capitan limestone. Blanchard and Davis⁴ recognized the gradation of sandstones below the Capitan into limestones at Goat Seep, but considered it a local feature; they correlated all the limestones farther north with the Capitan.

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¹Baker, C. L., op. cit., p. 114.

²Crandall, K. H., op. cit., p. 933.

³Darton, N. H., and Reeside, J. B., op. cit., p. 422, fig. 4.

⁴Blanchard, W. G., and Davis, M. J., Permian stratigraphy and structure of parts of southeastern New Mexico and southwestern Texas: Am. Assoc. Petroleum Geologists Bull., vol. 13, pl. 11, p. 969, 1929.

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GENERAL RELATIONS

The development of the Goat Seep limestone out of the sandstones of the Cherry Canyon formation can be observed to good advantage from the crest of the ridge between Bone and Shumard Canyons (pl. 12, B). The Capitan limestone rises to the east in a sheer wall, standing on the ledges of the "upper dark limestone" (Hegler and Pinery members of Bell Canyon formation). Below, long smooth slopes, broken here and there by limestone ledges (Getaway and South Wells members of Cherry Canyon formation) extend down toward the observer across the sandstones of the Delaware Mountain group. On the north side of Shumard Canyon, however, on the high spur that rises above the Victorio Peak limestone bench, thick limestone ledges are interbedded with the sandstones. At the same position on the next spur to the north, above Goat Seep and beyond Shirttail Canyon, the sandstone beds have disappeared and the limestones have merged into a single group of cliffs. They form the Goat Seep limestone, of which this is the type section. The two spurs are surmounted by the higher, steeper cliffs of the Capitan limestone, from which the Goat Seep cliffs are separated by ledges of the "upper dark limestone." This relationship indicates the Goat Seep limestone is of pre-Capitan age.

The view described above is shown on plate 12, B. The two spurs on which the Goat Seep limestone first appears lie below Shumard Peak near the middle of the view. The structure of the beds on the two spurs is shown on sections A—A' and B—B' of plate 9. The sequence on the two spurs is shown in sections 11 and 9, plate 6. Note how, in sections farther to the right on this plate, the Goat Seep limestones are traceable into the Getaway and South Wells limestone members.

To see the continuation of the Goat Seep toward the north, one must go several miles westward into the Salt Basin, where the whole west face of the mountains can be observed in panorama (pl. 5, B). The Goat Seep beds can there be traced northward along the mountain face from the two spurs near Shumard Canyon, rising and thickening, with the line of separation from the Capitan visible as a distinct, softer parting which rises diagonally across the cliffs until it reaches the mountain summit. Here the Goat Seep cliffs rise as high and stand as steeply as do the Capitan cliffs farther south, making it easy for the two units to be confused with each other. Nearer the observer, and fringing the base of the high mountains, are rugged lower limestone ridges which in another setting would be mountains in their own right. Closer examination shows that they are composed of downfaulted rocks, of which the most conspicuous constituent is again the Goat Seep limestone.

This view is seen in the panorama of plate 5, B, the structure of a part of which is shown on section K—K' of plate 17. The line of separation between the Goat Seep and Capitan appears low down on the cliff below summit 8356 (to left of Shumard Peak), and rises northward along it to the summit, which it reaches on the north slope of Bartlett Peak. Notice that between Shumard Peak and Bush Mountain the formation is massive and stands in sheer cliffs, but that farther north, near Blue Ridge, it is bedded and forms ledges.

SOUTHERN EXPOSURES

On the west side of the Guadalupe Mountains, the Goat Seep limestone thus makes its appearance above Goat Seep in Shirttail Canyon, or several miles north of the south edge of the Capitan limestone at El Capitan. It is formed by the northward thickening of the limestone beds of the Getaway and South Wells members (as shown on pl. 6). Like the Bone Spring flexure, the line of transition between it and the Cherry Canyon formation trends northeastward at an acute angle to the trend of the escarpment (fig. 8). Near Shumard and Shirttail Canyons more limestone is thus present on the points of the projecting spurs than in the canyons that are cut farther to the east.

The deposits, on the southeast margin of the Goat Seep, exposed on the ridge between Shumard and Shirttail Canyons (sec. 11, pl. 6), consist of massive lenticular, gray, dolomitic limestones in beds as much as 10 feet thick, many of which rest on channeled surfaces of the underlying sandstones or slabby limestones. The massive beds commonly contain angular limestone pebbles and fragments of fossils. Nearly all the intercalated sandstones pinch out a little farther north (sec. 9, pl. 6), but a layer at the top, in the position of the Manzanita member, persists for several miles, forming the parting of soft beds between the Goat Seep and Capitan which may be recognized on the cliffs from a distance.

North of Shirttail Canyon, the formation thickens rapidly to 1,200 feet at Bush Mountain, a prominent point on the escarpment 1-1/2 miles beyond (sec. 6. pl. 6). The lower half of the formation in this vicinity consists of light gray, dolomitic limestone, weathering to dirty-gray, jagged surfaces, in beds 10 to 50 feet thick, interbedded with some buff, calcareous, medium-grained sandstone. Some of the limestones are crowded with the remains of fusulinids, now preserved only as molds, and hence unidentifiable.

The upper half of the formation, below Bush Mountain, stands as a single, massive bed of limestone, without trace of bedding planes. Its upper part, where studied on the mountain crest a short distance south of Bush Mountain, is a sandy, buff, dolomitic limestone, containing casts of brachiopods, pelecypods, and fusulinids. Upper beds of the formation of similar character are exposed also on the slopes of the northern Patterson Hills to the southwest, and of the head branches of Pine Spring Canyon and North McKittrick Canyon to the northeast (pl. 3). The line of separation between them and the Capitan is not as clear as on the cliffs near Bush Mountain. They differ from the Capitan in being thick bedded, rather than wholly massive, as well as being more dolomitic, and in places somewhat sandy.

The following analysis was made of a white dolomite from the lower part of the Goat Seep limestone collected on one of the foothill ridges 2-1/2 miles northwest of Bone Canyon:

Analysis of white dolomite from the lower part of the Goat Seep limestone
[Analysis by K. J. Murata; note on insoluble residue by Charles Milton]

	Percent
Inorganic insoluble	0.85
Organic insoluble	.09
R2O3(mostly Fe2O3)	.28
CaCO3	55.21
MgCO2	43.07
Ca3(PO4)2	None
	99.50

NORTHERN EXPOSURES

The Goat Seep forms a thick, homogeneous limestone mass only in the vicinity of Bush Mountain. Northward as well as southward, it thins and contains more interbedded sandstones.

At Cutoff Mountain (sec. 1, pl. 6), in the northwest part of the area, it is 560 feet thick. Here, most of the lower half of the formation is thick-bedded, buff, calcareous sandstone, with a few interbedded limestone layers. The sandstones, like those in the Brushy Canyon formation to the south, contain fusulinid molds, are cross-bedded, and are moderately coarse-grained. A specimen of one of the sandstones, studied under the microscope by Ward Smith, consists of well-rounded quartz grains as much as 0.5 millimeter in diameter, many calcite grains of elastic origin, and some grains of zircon, all set in a calcareous matrix.

In the upper half of the formation, the sandstones are finer-grained and form thinner members. Between are many thin- to thick-bedded, light-gray limestone layers. The limestones are similar to those in the overlying Carlsbad limestone (equivalent to the Capitan farther south), but are not as thinly laminated, have a darker weathered surface, and do not contain the calcareous pisolites that are characteristic of the Carlsbad. East of Cutoff Mountain, on the east side of West Dog Canyon a mile north of Lost Peak (sec. 2, pl. 6), there is near the top of the formation a bed of dense, gray, petroliferous, calcitic limestone, which contains brachiopods and pelecypods (locality 7603).

Rocks similar to those on Cutoff Mountain are exposed some miles to the east on the lower slopes of the escarpment on the east side of Dog Canyon. This is the area in which the name Dog Canyon limestone was applied by Lang.⁵ Their exposures are shown in the panorama, plate 14, A, where they form the lower ledges on the distant escarpment, that are delimited above by slopes formed on the basal sandstone beds of the Carlsbad. As shown in the panorama, the rocks extend northward along the escarpment into New Mexico, beyond the area studied. They extend also into the head of North McKittrick Canyon, which appears in the distance on the panorama. In that canyon, as shown on plate 3 and on section E—E', plate 17, they dip southeastward beneath the Capitan limestone.

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⁵Lang, W. B., op. cit., p. 858.

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STRATIGRAPHIC RELATIONS

In all parts of the area, there was probably continuous deposition from middle Guadalupe into upper Guadalupe time, with only slight changes in sedimentation and faunas.

In field mapping, an attempt was made to draw the upper boundary of formations assigned to the middle part of the Guadalupe series at horizons that could be successfully traced. Thus, in the Delaware Mountains to the southeast, the top of the Cherry Canyon formation is drawn at the base of the Hegler limestone member of the Bell Canyon formation. This is the base of the lowest bed that grades into the Capitan limestone to the northwest. In the northwest part of the area, the top of the Goat Seep limestone is drawn at the base of the prominent sandstone that forms the lowest bed of the Carlsbad limestone.

In the intervening area, however, beds of both middle and upper Guadalupe age are of reef facies, and massive Goat Seep limestone is overlain by massive Capitan limestone. Here, the boundary is not easy to trace, although it is believed that the contact in most places has been located with a fair degree of certainty.

FOSSILS

The middle part of the Guadalupe series in the area studied contains abundant and interesting faunas, very few of which were known prior to this investigation. Girty,⁶ in his original work on the Guadalupian fauna described two lots of fossils (localities 2903 and 2931) from beds now known to belong to the lower part of the Cherry Canyon formation, but the main fossiliferous zones higher up had not then been discovered. However, his collections from beds higher and lower than the middle part of the Guadalupe series and from the southern Delaware Mountains included many of the species now known to occur in the middle part. Brachiopod species characteristic of the middle part of the Guadalupe series have been described by King⁷ from equivalent strata in the Glass Mountains. Ammonoids from the Cherry Canyon formation were collected by J. W. Beede in the early 1920's, and were afterwards described by Plummer and Scott.⁸

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⁶Girty, G. H., The Guadalupian fauna: U. S. Geol. Survey Prof. Paper 58, p. 21, 1908.

⁷King, R. E., The geology of the Glass Mountains, part 2: Texas Univ. Bull. 3042, 1931.

⁸Plummer, F. B., and Scott, Gayle, Upper Paleozoic ammonites in Texas: Texas Univ. Bull. 3701, p. 27, 1937.

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In the southeast part of the area studied, three main fossiliferous horizons are represented in the new collections. The lowest, called for convenience in this report the sub-Getaway fossil zone, lies between the Getaway limestone member of the Cherry Canyon formation and the uppermost massive sandstones of the Brushy Canyon formation. The next lies in the Getaway limestone member, and the highest in the South Wells limestone member. Poorly preserved fossils occur also in thin limestone beds between the Getaway and South Wells limestone members, and in the overlying Manzanita limestone member, but none has been collected by Fountain or me. The interval between the South' Wells member and the Hegler member at the base of the succeeding Bell Canyon formation, amounting to several hundred feet of beds, is thus poorly known paleontologically.

In the northwest part of the area, fossils occur sporadically in both the sandstone tongue of the Cherry Canyon formation and the Goat Seep limestone. These fossils were unknown prior to the present investigation, and even now are represented by only small collections.

CHERRY CANYON FORMATION

SUB-GETAWAY FOSSIL ZONE

The 100 to 200 feet of beds that separate the top of the Brushy Canyon formation from the base of the Getaway limestone member of the Cherry Canyon formation are mostly thin-bedded sandstone, but here and there occur lenses and channel fillings of sandy limestone in which fossils are abundant. The two lots of fossils (Nos. 2903 and 2931) from Guadalupe Canyon, described by Girty in 1908, apparently came from these beds. Included in these collections was the ammonoid Pseudogastrioceras serratum (Girty). Fusulinids are abundant in the sub-Getaway beds, but none has been collected or identified. The species that occur above and below the zone are the same, so it is unlikely that those in the zone between have any novel features. Dr. Girty reports as follows on the remainder of the recent collections:

This unit proves to be highly fossiliferous and the following summary covers five large collections which, taken together, present a rich and diversified fauna. One of the collections (No. 7729) appears to have been made at nearly the same locality and horizon as one of my original collections (No. 2931), which may be taken as a standard of comparison.

Fusulinids that were present in the original collection are present also in the later ones. Corals and bryozoans are sparingly represented in the later collections, and not at all in the original one. The corals belong to a single species of Lophophyllum, or a genus of similar construction. The bryozoans also have but a limited representation, the most common genus being Fistulipora, but with Stenopora, Batostomella, Septopora, and Acanthocladia also present.

Among the brachiopods, the orthoids are all but absent; they were entirely so in the original collection. A single specimen of Enteletes (E. dumblei Girty?) was found in one collection, and an indeterminable specimen of the same genus in another. Meekella continues to be present and is abundant in several collections. It seems to be confined to a single species which may provisionally be identified as M. attenuata Girty. Mention should also be made of a large and singularly marked dorsal valve which undoubtedly belongs to a new species, but the genus is uncertain as between Derbya and Orthotetes. The Orthotetinae were not represented at all in the original collection.

Chonetes, which has been rather sparingly present in the lower beds, occurs in all five collections. All but a few specimens belong to one species which appears to be a large form of C. subliratus Girty. The genus was found in the original collection, but the species was not determined.

The Producti are extremely abundant and varied. They are especially so at station 7471, and rather rare at station 7670. I propose to mention only the strongly characterized and interesting types, but there are many others whose relations are uncertain. The original collection contains species identified as Productus guadalupensis Girty, P. meekanus Girty, P. signatus Girty, P. signatus Girty var., P. sp. e, P. subhorridus rugatulus Girty, and P. walcottianus Girty. The later collections contain P. guadalupensis Girty with several varieties, P. (Cancrinella) signatus Girty, P. (Pustula) subhorridus Meek var., and P. walcottianus Girty. In addition, they contain the following species that had not previously been reported: P. comancheanus Girty, P. texanus Girty, P. aff. P. popei Shumard, P. aff. P. longus Meek, P. aff. P. multistriatus Meek, P. (Waagenoconcha) montpelierensis Girty, P. (Cancrinella) aff. P. cancriniformis Tschernyschew, and P. (Marginifera?) eucharis Girty. They also contain Aulosteges guadalupensis Shumard, which was not found in the original collection, and Prorichthofenia permiana (Shumard), which was.

Camerophoria (C. venusta Girty) occurs here, as in the lower beds. Rhynchonellids are abundant, especially Wellerella texana (Shumard), with several varieties. Among the novelties are two new species of Wellerella and Leiorhynchus weeksi var. nobilis (Girty), while Rhynchopora taylori Girty appears in every collection save one. None of these were represented in the original collection except Wellerella texana (Shumard), which was assigned to Pugnax osagensis Swallow?.

Terebratuloids are almost absent, and they were entirely so in the original collection. Aside from three or four fragmentary specimens, there is one that appears to belong to Dielasma cordatum Girty. The original collection contained no representation of the genus Spirifer, but they are abundant in the later ones. S. sulcifer Shumard appears for the first time, and S. pseudocameratus Girty appears in several collections. This species has not been recognized in lower horizons, although at least some of the imperfect specimens cited as S. aff. S. triplicatus Hall may belong to it. Spiriferina is rather sparingly represented, but I recognize three species, S. angulata King, (probably a synonym of S. haarmani Haack) S. laxa Girty, and S. hilli Girty? The original collection contained only one species, provisionally referred to as S. billingsi (Shumard). Ambocoelia. (A. arcunata Girty) is fairly abundant, but Composita is unusually rare. Most of the specimens seem to be referable to C. emarginata affinis Girty, but C. angusta King is also present. Hustedia is fairly abundant and persistent. Aside from the ubiquitous H. meekana (Shumard), I have identified H. bipartita Girty in one collection. Neither Ambocoelia, Composita nor Hustedia were found in the original collection, but Leptodus americanus Girty occurs in both the original and later ones.

The original collection from this general horizon contained a varied pelecypod fauna, and it is closely reproduced in the later ones with, of course, some additions. In fact, the pelecypods for the the first time occur in sufficient numbers and quality to invite comment. It seems to be true of the collections that where the brachiopods are abundant and varied the pelecypods are few, and vice versa.

The original collection contained an unidentifiable species of Edmondia and a small specimen identified as Edmondia? bellula Girty, which was described from the Capitan limestone. The new collections contain a large, subcircular species (possibly Edmondia sp. f of Professional Paper 58), which resembles E. circularis Walcott, but is probably new. Nucula, represented in the original collection by an unidentified species, is not rare. It may be provisionally designated as Nucula aff. N. beyrichi von Schauroth.

Parallelodon was, in the original collection, represented by P. multistriatus Girty and P. politus Girty, both described from the Capitan limestone. In the recent collections, the genus is abundant and varied. In addition to the two species just named, there are two new ones. One is large and marked by very coarse and strong radial costae. It recalls P. sangamonense (Worthen), but is clearly distinct. The other is remarkable for an extremely prominent umbonal ridge.

Schizodus was not present in the original collections, but it appears to be rather abundant, and is represented by two species, S. ferrieri Girty, and Schizodus aff. S. rossicus de Verneuil. Three aviculoid shells were recognized in the original collection, identified as Bakewellia? sp., Pteria richardsoni Girty?, and Pteria sp. P. richardsoni has also been recognized in one of the later collections. The original collection contained a species of Myalina, cited as M. permiana Swallow?, and the same species occurs in several newer collections, although as to identification, we know Swallow's species only by the grace of Meek and Hayden, and even so, only as a probability.

The Pectens, in the broad sense, seem rather more varied in the original collection, where they were represented by forms identified as Camptonectes? papillatus Girty, Aviculopecten delawarensis Girty, Acanthopecten aff. A. carboniferus Stevens, and Pernopecten obliquus Girty. The more recent collections contains Aviculopecten delawarensis Girty (which should probably be removed to Deltopecten), with two additional species, D. vanvleeti Beede and D. coreyanus White. Camptonectes papillatus Girty is also present, and likewise a new species, apparently of the same genus, as well as Pernopecten? obliquus Girty. In this connection, mention may be made of two undetermined species which apparently belong to Branson's genus Cyrtorostra, although that name seems to cover about the same sort of shells that European writers, including Waagen, refer to Oxytoma. These forms were not found in the original collections, nor were any representatives of Pseudomonotis, which are present in the later ones. Two species can be distinguished: one is related to P. hawni Meek and Hayden, but is probably new; the other, also probably new, is distinguished by its very large size, but is too poorly represented to be identified or described.

Astartella nasuta Girty, which was described from the Glass Mountains, is present in both the original collection and the later ones. Pleurophorus was represented in the early collection by P. delawarensis Girty, and by the possibly related Cleidophorus pallasi delawarensis Girty, the type specimens of both species having been found at this horizon. Both species occur in the collections of recent date, besides several other species of Pleurophorus, one related to P. occidentalis Meek and Hayden, the others new or undetermined.

A scaphopod, identified as Plagioglypta canna White?, was found in the first collection, and in the new ones as well.

. The gastropod representation in the early collection was no less varied than the pelecypod representation. It included eight species of Pleurotomaria, that term being employed in a broad sense. These are P. multilineata Girty, P. sp. d, P. euglyphea Girty, P. pseudostrigillata Girty? (the originals being from the Bone Spring limestone), P. arenarea Girty, P.? planulata Girty, P.? delawarensis Girty, and P.? carinifera Girty.

In the more recent collections also, the gastropods are well represented, but they are practically confined to one collection (locality 7729). The eight species of Pleurotomaria all occur in the later collections, besides one or two new ones. Details here would have little point, inasmuch as the new species can not be cited without further study.

Among the bellerophontids, the original list included only Bucanopsis sp. and Warthia americana Girty. The new collections do but little better. They give us Warthia americana, two indeterminable species of Bucanopsis, and an indeterminable species of Euphemites, resembling E. carbonarius (Cox) on a large scale.

The residue of the gastropods in the original list consisted of Naticopsis sp., Pseudomelania sp. a, Bulimorpha chrysalis delawarensis Girty, and Macrochceilina? sp. a. In the new collections, we have Naticopsis sp., Pseudomelania sp. a, and Bulimorpha chrysalis delawarensis Girty, but in addition are a species of Trochus ?, an indeterminable species of Omphalotrochus, and Ianthinopsis a. sp., which seems to be rather abundant.

The trilobite Anisopyge perannulata (Shumard) occurs in the old collection and in the new ones, a survival from the Bone Spring limestone. It continues, in fact, into the highest fossiliferous beds of the Guadalupe section.—Girty manuscript.

PLATE 14.—PANORAMIC VIEWS IN NORTHERN AND SOUTHERN PARTS OF AREA STUDIED. Qoa, Older alluvial deposits; Pcb, Carlsbad limestone; Pcb (ss), basal sandstone member of Carlsbad limestone; Pg, Goat Seep limestone; Pdc, Cherry Canyon formation; Pdy, Brushy Canyon formation; Pbc, Cutoff shaly member, and Pbl, black limestone beds of Bone Spring limestone. F, Fault. A, Dog Canyon and escarpment on its east side, from Lost Peak. B, Mouth of canyon west of Chinaman's Hat, looking south. Shows outcrop of Border fault. C, View east, showing Chinaman's Hat, with rim of Delaware Mountains in background.

GETAWAY LIMESTONE MEMBER

In the Getaway limestone member, which lies a short distance above the beds containing the above described fauna, fossils are still more abundant and have been collected at numerous localities, of which 13 are herein reported by Dr. Girty. All the collections came from the western part of the Delaware Mountains in an area extending some eight miles south of Pine Spring and El Capitan, and include material from Getaway Gap (7621), Guadalupe Summit radio station (7463, 7474, 7615), near Guadalupe Pass (7422, 7465, 7475), and the hills south of Pine Spring Camp (7406, 7470, 7641) (pl. 2). The member was apparently not represented by collections in the original work on the Guadalupian fauna.

The Getaway member contains numerous fusulinids belonging to the genus Parafusulina. Of them, the following species have been identified by Dunbar and Skinner:⁹ P. maleyi Dunbar and Skinner, P. maleyi referta Dunbar and Skinner, P. rothi Dunbar and Skinner, and P. sellardsi Dunbar and Skinner?. It will be recalled that these same species occur also in the underlying Brushy Canyon formation. They have not been found above the Getaway member. In addition, Needham¹⁰ has identified P. dunbari Needham from beds 700 feet below the Capitan limestone on the south slope of El Capitan. This horizon is probably in the Getaway member. Dunbar and Skinner¹¹ consider his species a synonym of their P. rothi.

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⁹Dunbar, C. O., and Skinner, J. W., Permian Fusulinidae of Texas: Texas Univ. Bull. 3701, p. 593, 726-727, 729, 1937. Horizon cited as "limestone in lower part of middle division."

¹⁰Needham, C. E., Some New Mexico Fusulinidae: New Mexico School Mines Bull. 14, p. 13. 1937.

¹¹Dunbar, C. O., and Skinner, J. W., personal communication, 1938.

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Among the cephalopods, the nautiloids are represented by varied material, although only a few specimens are present in any one collection. In this group, Miller¹² has recognized the following: "Orthoceras" sp., Titanoceras sp., Metacoceras shumardianum (Girty), Tainoceras sp., and Stenopoceras? sp. The ammonoids are less well represented, only a few specimens having been found and these belonging to genera that are not of great value for zonation and correlation. From the member Miller and Furnish¹³ have identified Pseudogastrioceras roadense (Böse) ?, Pseudogastrioceras sp., Medlicottia burckhardti Bose, and Paraceltites ornatus Miller and Furnish?.

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¹²Miller, A. K., memorandum, May 1939.

¹³Miller, A. K., and Furnish, W. M., Permian ammonoids of the Guadalupe Mountain region and adjacent areas: Geol. Soc. America Special Paper 26, pp. 11-12, 1940.

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Regarding the remainder of the fauna, Dr. Girty reports as follows:

The sponges, which are a really remarkable feature of the Guadalupian fauna but heretofore have not figured to any extent, now appear in some force. Stable generic identifications must necessarily await more careful study than I=it has been possible to devote to this difficult group, but for present purposes record may be made of two new species of Amblysiphonella, a specimen of Guadalupia zitteliana Girty? (described from the Capitan limestone), and Anthracosycon ficus Girty?. The latter species, with another unnamed species of the same genus, was found in one of the original collections from the Bone Spring limestone, and these two are about the only representatives of this group that have been observed below the Getaway limestone member.

Corals continue to be poor in numbers and variety. They are exceptionally so when one considers the abundance and diversity of other forms in these collections. The cup corals appear in only six collections, mostly a single specimen in each. As provisionally identified, they represent but a single species, and it appears to be the same as that found in the preceding fauna, which was cited as Lophophyllum? sp. The columella in these corals is more complicated than it is in the more simple and typical forms of Lophophyllum, and more complicated than it is in some of the forms that pass as L. proliferum in the Carboniferous faunas of the Mid-continent area. Here for almost the first time appears the delicate compound coral Cladopora spinulata Girty, which was first described from the "upper dark limestone" (Finery member of Bell Canyon formation).

Many bryozoans can be identified, even generically, only by means of thin-sections, so no more than a tentative outline can be given of those in the Getaway limestone. Fistulipora, represented by P. grandis guadalupensis Girty, and possibly a new species, is rather abundant, and also Acanthocladia guadalupensis Girty. Aside from these, however, the bryozoans, although varied, have a small and scattered representation. The following forms, many subject to reidentification, have been encountered: Anisotrypa? sp. Leioclema? sp., Batostomella? sp., Fenestella sev. sp., Rhombopora sp., Coeloconus? sp., Rhabdomeson? sp., Cystodictya sp., and Domopora terminalis Girty. The series of forms tentatively referred to as Domopora are much more abundant at higher horizons, and notably in the Pinery member.

The brachiopod genus Enteletes, which is so abundant in some of the older faunas, is absent from the Getaway limestone, as are the related genera Rhipidomella and Schizophoria, which occur here and there in lower horizons.

Of the Orthotetinae, Meekella continues to be by far the dominating type. M. attenuata Girty or M. multilirata Girty, or sometimes both, occur in most of the collections. We also have Derbya n. sp., a large and remarkable form, which was noted in the underlying fauna, but not identified because of the absence of the ventral valve. There are a few other rarer forms that do not belong to any of the three species mentioned, but whose generic status cannot be determined, as they are represented mostly by dorsal valves. One of these may be Streptorhynchus pyramidale King.

Chonetes occurs in almost every collection, and is generally abundant. We seem to have here both C. subliratus Girty, which was described from the Pinery limestone, and C. hillanus Girty, which was described from the Capitan limestone. Apparently the latter is more common, but the two species are difficult to distinguish.

The productids are exceedingly numerous and varied, almost thirty different forms having been discriminated, including a number of varieties and several new species. The following are the most noteworthy: Productus popei Shumard (in the sense of King, rather than Girty), P. popei minor King, P. guadalupensis Girty, P. walcottianus Girty, P. walcottianus costatus (King), Productus aff. P. longus Meek, P. aff. P. geniculatus Girty P. occidentalis Newberry, P. texanus Girty, P. capitanensis Girty, P. (Pustula) subhorridus Girty and one or two varieties, P. (Pustula?) pileolus Shumard, P. (Waagenoconcha) montpelierensis Girty, P. (Cancrinella) signatus Girty, and a number of varieties, P. (Cancrinella?) phosphoticus Girty, P. (Marginifera?) wordensis (King), P. (Marginifera?) sublevis King, and P. (Avonia) n. sp.

Some of these species, for instance P. capitanensis Girty and P. (Pustula?) pileolus Shumard, which were described from the Capitan limestone, have not been found in beds below the Getaway, and some of the species found in the underlying beds, for instance P. comancheanus Girty, P. aff. P. multistriatus Meek and others, have not been found in the Getaway limestone. There is, however, such a general homogeneity in the productid representation that it is doubtful whether these items of disagreement have much importance.

A rather noteworthy change comes in at this horizon in the genus Aulosteges. In the black limestone beds of the Bone Spring A. magnicostatus Girty is abundant and also a species identified as A. subcostatus King. The genus was not present in the Victorio Peak gray member, but it reappears in the Cutoff shaly member, which contains the first-named species and also A. hispidus Branson and A. guadalupensis Girty?. In the Brushy Canyon formation I found a single specimen of doubtful affinities which was not mentioned in the summary of that fauna. In the Getaway, the genus occurs in nearly every collection and in abundance. The prevailing species resembles A. guadalupensis Shumard, but is varietally, if not specifically distinct, and is also distinct from species of the genus in underlying faunas. With it occurs a different and much rarer species, possibly related to A. wolfcampensis King, represented by only three specimens.

Prorichthofenia occurs in every collection save one, and is abundant in most. The species seems to be that of the preceding faunas, P. permiana (Shumard). Leptodus is fairly persistent in the collections, but is abundant in only one of them. In others, it is represented only by a specimen or two. Most or all of the specimens belong to L. americanus Girty.

Camerophoria continues to be represented by C. venusta Girty, but it is accompanied by a smaller species provisionally referred to C. deloi King, and a third form which may be only a variety of C. venusta.

The rhynchonellids are abundant and highly diversified. Many changes are noted from the rhynchonellid representation of the beds below. In general, these shells show a closer agreement with the rhynchonellid faunas higher in the section. A noteworthy feature of this element in the Getaway fauna is the introduction for the first time, and also at some localities in abundance, of the large shells cited under the genus Liorhynchus. More specifically, I recognize Wellerella? swallowiana (Shumard), W. swallowiana var., W.? pinguis (Girty), Wellerella aff. W.? indentata (Shumard), Camarotochea? longaeva (Girty), C. n. sp., Rhynchopora taylori Girty, R. illinoisensis (Worthen), Leiorhynchus weeksi nobilis (Girty), and L. bisulcatum (Shumard).

The terebratuloids are rather numerous and varied. I recognize Dielasma spatulatum Girty, D. prolongatum Girty, Dielasmina? a. sp., Heterelasma? n. sp., and Cryptocanthia a. sp.

Spirifer is represented by two species, a large form which is common, and which is provisionally referred to S. latus King (his Spirifer (Neospirifer) mexicanus latus), and a much rarer form which may be S. sulcifer Shumard, if one may assume that Shumard's figure is poor (which is probable). Spiriferina is present in most collections, but the specimens are so few and so poor that most of them cannot safely be identified. Some, however, appear to belong to S. hilli polypleurus Girty, some to S. laxa Girty, and some to a species related to S. welleri Girty, but probably new. Ambocoelia is present in a number of collections and is abundant in some of them. It is a remarkably large species and the ventral valve looks like a rather small, gibbous Squamularia. The species is new.

Composita, as would be expected, is present in most of the collections, sometimes in abundance. There are at least two distinguishable species. One, which is exceptionally large, may be cited as C. emarginata affinis Girty. The other is a rather small form, but apparently mature, if one may judge by its strong convexity and well-developed fold and sinus. It closely resembles C. mexicana (Hall).

Hustedia also is represented in almost every collection, and in some abundantly. Most of the specimens are here identified as H. meekana (Shumard), although H. bipartita Girty and a variety of it are also present. The specimens of H. meekana, some of which are exceptionally large, show considerable variety, and under careful study may be susceptible of minor subdivision.

In general, the pelecypod fauna of the Getaway limestone, while showing some departures from that of the sub-Getaway zone, does not show as many as might be expected, in view of the fact that pelecypods are abundant at only two localities in the sub-Getaway.

Solenomya is represented by two more or less doubtful species, one of which appears to be related to S. radiata Meek and Worthen.

Edmondia is represented by several species, but most of the specimens are so poor that the generic identifications are hypothetical. Of the uncertain forms, one is a large subcircular species related to E. circularis Walcott, and not improbably the same species that was mentioned in the sub-Getaway fauna. The other is a much smaller form related to E. gibbosa Swallow. However, Edmondia and Astartella have a close superficial resemblance and are difficult to distinguish in poorly preserved material; the specimen may therefore be a very robust species of the latter.

Nucula and Leda, as in the preceding fauna, are almost unrepresented. The collection contains a single unidentifiable specimen of the one, and a single specimen of the other, related to the common N. bellistriata (Stevens).

Parallelodon has much the same representation as in the preceding fauna, although the preservation of the material leaves much to be desired. It comprises a large and very coarsely costate species which is undescribed, and another species with out costae, which may be identical with P. politus Girty, and a third species which may be identified with P. multistriatus Girty.

Pteria (besides several doubtful species) is represented by a remarkable form resembling P. longa (Geinitz), but very much larger, nearly 80 millimeters long obliquely. This is probably the species figured in Professional Paper 58 as Pteria sp.

Myalina is moderately abundant in one collection but is represented by a single species in the others. Most of the specimens are in a poor state of preservation, and all may be referred to provisionally as M. permiana Swallow?, which was also identified in the sub-Getaway fauna.

Schizodus, which was scanty in the sub-Getaway fauna, and represented by small species related to S. rossicus de Verneuil, is here fairly abundant and represented by a large species. The specimens vary more or less in shape, some being similar to the Pennsylvanian species S. affinis Herrick, others to such species as S. harei Miller, and S. ulrichi Worthen. The possibility cannot be dismissed that this is S. phosphorianus Branson, for his type specimens appear to be fragmentary and preserved in a different manner from mine, which have been macerated.

The Pectenidae are numerous and diversified. Some of the species are uncommonly large. Many of the generic references are provisional, as are some of the specific identifications. Many of the specimens are not of the best, and obviously fail to show characters of importance. Besides a number of indeterminate forms, I recognize Acanthopecten a. sp., A. coloredensis (Newberry), Girtypecten sublaqueatus Girty, Deltopecten aff. D. providencensis (Cox), D. delawarensis (Girty), D. guadalupensis (Girty), D. vanvleeti Beede, and D. coreyanus White. The two species last mentioned are interpreted in the same manner as in my report on the fauna of the Manzano group. Pernopecten? obliquus Girty, which is rather rare, and Camptonectes n. sp. also belong here. The latter occurs sparingly in many collections, but is extremely abundant at station 7424. On the whole, this type of shell is more abundant and diversified than it was in the lower horizons. On the other hand, the interesting forms belonging to Cyrtorostra or Oxytoma have not been found. There is, however, an uncertain specimen that looks much like Cyrtorostra sexradiata Branson, if, indeed, his species is congeneric with the others.

Of Lima I have only one specimen, a large, finely striated form, which probably represents a new species, although the specimen is hardly suitable for use as a type.

The pleurophorids, although numerous and varied in the Getaway member, are difficult to identify generically or specifically. Some are broken, others have indefinite outlines. Some are internal molds or show no surface characters, and some may be compressed and have a different aspect from better preserved specimens that are probably of the same species. Because of their defects, many specimens cannot be distributed satisfactorily between the genera Myoconcha, Pleurophorus, and Cleidophorus. They suggest gradation between the genera, and becloud identification of species.

As in the preceding sub-Getaway fauna, the Getaway contains good representations of Myoconcha costulata delawarensis Girty, Pleurophorus delawarensis Girty, and Cleidophorus pallasi delawarensis Girty. The second species is represented by a few specimens of normal size and possibly by an extremely large internal mold of similar shape but nearly three times the size of the holotype. I have no misconception regarding the form called Cleidophorus pallasi delawarensis. It probably does not belong to the genus Cleidophorus, and may be a Pleurophorus. The formula adopted was for the purpose of noting a resemblance to the European species which has passed as Cleidohorus pallasi de Verneuil. The internal ridge or plate which has passed as characteristic of this genus, and a semblance of which has been found in my specimen also, is really the boundary of the anterior muscle scar.

In addition to these, the Getaway contains a shell that resembles Myoconcha costulata delawarensis in a general way. It is much larger than the holotype, and one of the specimens shows that the surface is marked by very fine radial striae, whereas the holotype is supposed to be without sculpture. There is also a very large fragmentary specimen which probably represents a new species of Myoconcha, but it could not be made the basis of a description.

Another smaller and still more refractory group of specimens are more the type of Pleurophorus as it is generally identified. It is doubtful whether the most careful work would resolve these shells satisfactorily into genera and species. Specimens of Parallelodon may be among them, especially representing such forms as are without radial striae or have only very fine ones. There may be also specimens of Allorisma—not Allorisma of the type A. terminale Hall, but of other types that have been referred to that genus. The absence of typical species of this genus (such as A. terminale Hall and A. capax Newberry) is a noteworthy feature of the fauna.

The gastropods of the Getaway limestone are fairly numerous and varied, and add considerably to the Guadalupian fauna. The information which they afford, however, is in many cases rendered indefinite because specimens have lost the surface characters, so that identification is rendered hazardous or impossible. This loss is even more detrimental in the case of the gastropods than it is with the pelecypods.

The bellerophontids are mainly in the form of molds and such specimens are beyond the pale of scientific classification. All belong to small species. Among those that are susceptible to some sort of classification there is one specimen that appears to be specifically identical with the form from the southern Delaware Mountains that I figured as Bellerophon crassus Meek and Worthen, an identification which I now propose to abandon. There are also two indeterminable species of Bucanopsis, represented by fragments, and a species of Euphemites which might be described as a large, slender form of E. carbonarius (Cox).

The pleurotomaroids, like the bellerophontids, are mostly indeterminable by reason of exfoliation, which has deprived them of their sculpture, upon which the specific and even the generic classification depends. There is a rather diversified pleurotomaroid fauna in the bed below the Getaway and some of the species will undoubtedly appear among the identifiable specimens from the Getaway itself. At present, I am prepared to identify Pleurotomaria euglyphea Girty, and P. n. sp.

Several poorly preserved specimens apparently belong to Straparollus sulcifer (Girty), described from the "upper dark limestone" (Pinery member), and the related genus Omphalatrochus is represented by a new species.

Naticopsis is represented by several species, although their relations to one another and to species in the literature are not readily determinable because of their condition. One species (it is an internal mold or partly macerated) which appears to belong to this genus is remarkable for its large size. Others, on the contrary, are very small. An undetermined species of Naticopsis was found in one of the original collections from the sub-Getaway zone, and it is quite likely that the same species occurs in the Getaway fauna. The peculiar shell that for the time being can be designated as Ianthinopsis n. sp. occurs in several collections. It has already been noted in the fauna preceding this one.

The characters on which rest the distinction between Bulimorpha, Meekospira, and Strobeus are rarely observed. With this qualification as to generic identification, the fauna of the Getaway limestone contains two species of Bulimorpha, one of them uncommonly large and both new. It is possible, however, that B. chrysalis delawarensis Girty, which was described from the sub-Getaway zone, was based on an immature specimen of one of them. There is also a small, globose species of Strabeus very similar to S. littonanus (Hall) of the Spergen limestone, which is also new. I might remark that the scarcity of shells of this genus in the Guadalupian fauna, as compared with a number of faunas of Pennsylvanian age, is a noteworthy feature.

The Platyceras tribe is met with for the first time in the section in the Getaway fauna. With full recognition that not only specific but generic distinctions in these shells are in dispute, it would appear that the three specimens in these collections probably represent two new species, one of Platyceras, and the other of Orthonychia.

Lastly, among the gastropods, we have two poor specimens which belong to a species that was briefly described in Professional Paper 58 as Pseudomelania sp. a. If not the same species, this is a closely related one, and it is remarkable for its numerous flat-sided whorls that make up the spire which appears to be more cylindrical than conical in shape. Unfortunately, the specimens are decorticated and no better generic reference than the one originally made can be suggested.

Of the crustaceans, the representation is all but restricted to the trilobite Anisopyge perannulata (Shumard), which is present in most of the collections. Ostracodes are a rare feature of the Guadalupian faunas, and they have not been mentioned in descriptions of the underlying faunas. In the Getaway limestone, they are also absent from all collections but one. In this one there is a small slab that is fairly packed with them.— Girty manuscript.

SOUTH WELLS LIMESTONE MEMBER

The South Wells limestone member is represented by collections from only the southeastern part of the area studied as: near Long Point (No. 7641), 2 miles southeast of the D Ranch South Wells (No. 7649), and in the Pinyon Hills (Nos. 7658, 7664, and 7665) (pl. 2). Most of the fauna was unknown before the time of the present investigation, although ammonoids were collected from it near the South Wells in the early 1920's by J. W. Beede, and were afterwards described by Plummer and Scott.¹⁴ The sandy and dolomitic limestones of the member northwest of the localities mentioned, as in the foothills of the Guadalupe Mountains, contain poorly preserved fossils, but none has been collected and their character is unknown.

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¹⁴Plummer, F. B. and Scott, Gayle, Upper Paleozoic ammonites in Texas: Texas Univ. Bull. 3701, p. 27, 1937.

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The fossil-bearing beds in the southeast part of the area have yielded collections that are relatively small compared with those from the underlying Getaway member; also the fauna appears to lack the diversity of the older one. Two more or less distinct facies are present: One is gray, granular limestone which contains fusulinids, productid and spiriferoid brachiopods, bryozoans, and some pelecypods; the other is black, dense limestone, reminiscent of the black limestones of the Bone Spring, and like them containing great numbers of ammonoids. Associated with the ammonoids are abundant rhynchonellid brachiopods, particularly of the genus Leiorhynchus. The gray limestone facies is dominant at the Pinyon Hills localities; the black limestone facies is dominant at Long Point and near South Wells, although here also some of the gray limestone facies is interbedded.

In comparison with the Getaway fauna, fusulinids are considerably reduced in numbers. They have been seen in the foothills of the Guadalupe Mountains, but are too poorly preserved there to be collected or identified. Some have been collected in the Pinyon Hills, from which Dunbar and Skinner¹⁵ have identified Leëlla fragilis Dunbar and Skinner, and Parafusulina n. sp. This is the highest zone in the area at which the latter genus has been certainly identified. The next zone above from which fusulinids were collected during the present investigation is several hundred feet higher in the Hegler limestone member. Here the dominant genus is not Parafusulina but the related and younger genus Polydiexodina. In the southern Delaware Mountains, Skinner¹⁶ reports that he has collected Parafusulina and Polydiexodina within 75 feet of each other in the section but has never seen them in association.

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¹⁵Dunbar, C. O., and Skinner, J. W., Permian Fusulinidae of Texas: Texas Univ. Bull. 3701, pp. 593 and 727, 1937. Horizon referred to as "limestone in middle of middle division."

¹⁶Skinner, J. W., personal communication, August 1938.

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The ammonoids, which form an abundant and striking feature of collections made near Long Point and South Wells, have been described by Plummer and Scott on the basis of Beede's collections, and by Miller and Furnish¹⁷ on the basis of collections made during the present study. From this area, the latter have identified Medlicottia burckhardti Böse, Paraceltites ornatus Miller and Furnish, P. sellardsi Miller and Furnish, Pseudogastrioceras beedei (Plummer and Scott), P. roadense (Bose), Waagenoceras guadalupense Girty, and W. dieneri richardsoni Plummer and Scott. A few similar forms have been obtained also in the Pinyon Hills. With the ammonoids are a few nautiloids, which A. K. Miller has identified as Metacoceras sp. and "Orthoceras" sp.

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¹⁷Miller, A. K., and Furnish, W. M., Permian ammonoids of the Guadalupe Mountain region and adjacent areas: Geol. Soc. America Special Paper 26, pp. 10-11, 1940.

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Regarding the remainder of the fauna, Dr. Girty reports as follows:

The more lowly organic types are poorly represented. Fusulinids are present, but not abundant, and the sponges are apparently absent altogether. The corals are represented by two specimens, apparently belonging to the same species that has been cited in the faunas already reviewed as Lophophyllum sp.

The bryozoans are poorly represented. Fistulipora (F. grandis guadalupensis Girty?) continues to be the most abundant type. There are probably two species of Tabulipora. Domopora, which is so characteristic of the Pinery fauna, is represented by D. ocellata Girty. The absence of Fenestella, Polypora, Acanthocladia and other genera is more or less noteworthy.

Turning to the brachiopods: Enteletes and related genera are absent entirely. Meekella is present, but is represented by a few poor specimens, provisionally identified as M. attenuata Girty. Chonetes is present at one locality. It is difficult to tell whether the specimens belong to C. subliratus Girty or C. hillanus Girty, or both.

Productids are reduced in numbers and variety, as compared with those of the Getaway limestone. Many of the species are the same, but the specimens are fewer and poorer. The following provisional identifications have been made: Productus popei Shumard (as interpreted by King), P. (Marginifera?) wardensis (King), Productus sp. (possibly Avonia signata as interpreted by King, P. (Waagenocancha) montpelierensis Girty, P. (Cancrinella) signatus Girty with a variety or two, P. (Cancrinella?) phosphaticus Girty, and P. (Marginifera?) n. sp.

Aulosteges is present at one locality. The species seems to be the same as that which occurs in the Getaway limestone, where it was cited as A. guadalupensis Shumard var. Prorichthofenia permiana (Shumard) persists, and at one locality is relatively abundant. Camerophoria is represented by only a fragmentary specimen, probably C. venusta Girty.

The South Wells fauna is remarkable for the abundance and diversity of its rhynchonellid shells, and this fact is especially noteworthy in view of its paucity of other types. Some of the species are of large size, and they are especially abundant. Some of them resemble the species that were described by me as Pugnax bisulcata (Shumard), P. weeksi Girty and P. weeksi nobilis Girty. They appear to be the same species, wholly or in part, that King figures as Leiorhynchus bisulcatum (Shumard) and L. weeksi nobilis (Girty), but I am satisfied that my new specimens cannot be identified with the originals of the species just named in spite of a general resemblance to them. The shells of the present collection differ from the species named in size, and in number, strength, and distribution of the plications, so that if one wished, ten or a dozen species or varieties could be distinguished, all of them new: The best way to classify these protean shells must await more careful consideration than has yet been possible to give. The preceding Getaway fauna also was notable for the abundance and variety of its rhynchonellid shells, but in the South Wells fauna we seem to have a new dispensation. Many of the forms that occur in the South Wells fauna seem not to occur its the Getaway, and vice versa. Those forms that are similar or possibly the same are represented by few specimens. Among these forms mention may be made of Wellerella bidentata (Girty), Wellerella? pinguis (Girty)?, and Wellerella aff. W.? indentata (Shumard), all of which are scarce.

The terebratuloids are represented by Dielasma cordatum Girty, Dielasmina guadalupensis Girty, and probably by two species of Cryptocanthia (this generic reference subject to revision), one of them being a survival from the Getaway limestone. These shells are rather abundant and form a noteworthy feature of the fauna. Their large size is in striking contrast to the Pennsylvanian species of the genus and, as they have a septum in the dorsal valve, it is likely that they will prove to be generically new.

Spirifer is represented by one specimen which appears to be S. sulcifer Shumard as interpreted heretofore, and by fragments of what appear to be several other species, one at them related to S. triplicatus Hall. Spiriferina is in like manner represented by a few fragmentary specimens. Two species can be distinguished, one of which can provisionally be identified as S. laxa Girty. Squamularia is doubtfully represented by a single specimen.

Composita is represented by numerous specimens, and can be divided into two more or less interlocking species. One is C. emarginata affinis Girty; the other is very close to C. subtilita (Hall). Hustedia continues to be present as H. meekana (Shumard).

In consonance with the restricted representation of other groups, the pelecypods of the South Wells fauna are confined to the genus Parallelodon, to the Pectenidae, and to the genus Myalina. They are so poorly represented that they could hardly demonstrate any close affinity, or lack of it, with the pelecypod fauna of the Getaway limestone.

Parallelodon is represented by a small, fragmentary, and doubtfully identifiable specimen. It certainly does not belong to P. politus Girty, but might possibly be an immature specimen of P. multistriatus Girty. Myalina is doubtfully represented by a fragmentary specimen.

Among the Pectenidae, a fragmentary specimen of Deltapecten appears to be related to D. guadalupensis (Girty). A poor specimen of Pernopectin probably belongs to P.? obliquus (Girty). Finally, there is a peculiar form which suggests the species described as Aviculopecten montpelierensis Girty, a type of shell which has sometimes been referred to the genus Streblopteria. The Guadalupian form may not be congeneric with A. montpelierensis and its generic relations are uncertain from the material at hand.

The gastropods are still less distinctive in their relationships than the pelecypods. They include a probable new species of Capulus, a doubtful species of Pleurotomaria an imperfect specimen that probably belongs to Bulimorpha, an indeterminate species of Euomphalus, and an imperfect specimen that probably represents a new species of Omphalotrochus.

Anisopyge perannulata (Shumard), which has occurred in all the underlying faunas, and is encountered in those above, does not appear in the collections from the South Wells member—Girty manuscript.

MANZANITA LIMESTONE MEMBER

During field work both Fountain and I observed at many places in the orange-brown, earthy limestones of the Manzanita member the molds of ammonoids, crinoid stems, fusulinids, and other fossils, but were unable to collect identifiable material. Since then, Clifton¹⁸ has collected and identified fossils from the member at Long Point, apparently from the lumpy, slabby facies of the member. According to Clifton, the member here contains the following ammonoids: Medlicottia sp., Paraceltites ornatus Miller and Furnish, Cibolites uddeni Plummer and Scott, Pseudogastrioceras altudense (Böse), P. roadense (Böse), P. beedei (Plummer and Scott), P. cf. P. texanum Clifton, Agathiceras girtyi B&oum;se, Waagenoceras guadalupense Girty, W. dieneri Böse, W. richardsoni Plummer and Scott, and Timorites? sp. Associated with the ammonoids are brachiopods, pelecypods, sponges, a gastropod, a crinoid, and an echinoid. Clifton also notes that he and his associates have collected fusulinids from the member on Nipple Hill, but the identity of the species is not stated.

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¹⁸Clifton, E. L., Ammonoids from upper Cherry Canyon formation of Delaware Mountain group in Texas: Am. Assoc. Petroleum Geologists Bull., vol. 28, pp. 1644-1656, 1944.

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SANDSTONE TONGUE OF CHERRY CANYON FORMATION

The four preceding faunas (sub-Getaway, Getaway, South Wells, and Manzanita) all occur in the Cherry Canyon formation in the southeast part of the area, and lie one above the other in normal stratigraphic order. The next two faunas (sandstone tongue of Cherry Canyon and Goat Seep) lie in the northwest part of the area, in beds of approximately the same age as the preceding four, but of different facies. As will be seen from the descriptions, these differences in facies are reflected in the composition of the faunas of the two areas. The two faunas to the northwest resemble each other more than they do any of the four faunas to the southeast.

In the upper part of the sandstone tongue of the Cherry Canyon formation are calcareous layers that contain poorly preserved fossils, most of which are so silicified that their internal structure is destroyed; many remain only as molds. Collections were made at four localities; three of them (Nos. 7634, 7651, and 7728, pl. 2) were in the outcrops between Goat Seep and Cutoff Mountain, and one (No. 7647) was northwest of Cutoff Mountain and about 3 miles north of the New Mexico line.

The last named collection contains large fusulinids superficially similar to the species of Parafusulina in the Brushy Canyon and Getaway faunas to the southeast. The specimens are so completely silicified, however, that their internal structure is destroyed, and they are apparently not even generically identifiable. No ammonoids have been found in the sandstone tongue.

The greater part of the fauna consists of brachiopods, but a few bryozoans, pelecypods, and gastropods have been collected. Regarding these groups, Dr. Girty reports as follows:

Bryozoans are represented by a single specimen, probably belonging to the genus Septopora.

Enteletes is apparently represented by four species which may provisionally be identified as E. liumbonus King, E. angulatus Girty, a third uncommonly large form which may prove to be new, and a fourth distinguished by being marked with numerous fine plications. The specimens are, however, few and poorly preserved, adding difficulty to the discrimination of species in a genus in which discriminations are always difficult. The preservation of these specimens is poor but one or two may belong to the genus Meekella. This is especially true of the fourth species mentioned, which is represented by only internal molds of dorsal valves. These strongly suggest dorsal valves of Meekella (such as M. skenoides Girty), but the specimens seem to have a well-marked cardinal area and a cardinal process like that of Enteletes.

Chonetes is represented by an indeterminable specimen in the form of an internal mold.

Productids are fairly abundant and varied, relative to the other forms, but they almost defy classification. Most of the specimens are in the form of molds, so the identifications adopted indicate what the specimens might be if they were well preserved, rather than the presence of distinctive characters that can be definitely recognized. Besides several forms that are wholly unidentifiable, the following species may be cited as present: Productus guadalupensis Girty, P. texanus Girty, Productus sp. a (of Professional Paper 58), P. (Cancrinella) aff. P. meekanus Girty, and P. (Marginifera?) woogenianus Girty.

The rhynchonellids are represented by a single specimen which is very similar to Wellerella? swallowiana (Shumard). The terebratuloids are apparently absent. Poorly preserved specimens of Leptodus are present, apparently belonging to Laptodus americanus Girty.

Spiriferoids are fairly abundant. Three species of Spirifer can be distinguished, but they are more easily differentiated than identified. One which has fine fasciculate costae may be S. costella King. A second species which has coarse costae strongly grouped in bundles of three may be the species identified by King as S. pseudocameratus Girty, while a third form (a single poorly preserved specimen) may be the species be identified as Spirifer sulcifer Shumard.

To Spiriferina are attributed two specimens, although neither of them can be certainly distinguished from Spirifer. One may be cited tentatively as a large variety of Spiriferina hilli Girty. The other is more likely S. hilli polypleurus Girty. Squamularia is abundant in one collection. The specimens probably represent a new species related to S. guadalupensis (Shumard), but with a high cardinal area and fairly strong sinus in the ventral valve.

Of Composita there may be two species. One is very similar to C. subtilita (Hall), although reaching a rather large size in specimens. The other species is small, and is snore comparable to C. mexicana (Hall). Hustedia persists in the common species H. meekana (Shumard).

The mollusks are all but missing. One pelecypod probably belongs to Parallelodon multistriatus Girty; another is an indeterminable species of Aviculopecten; and a third is a somewhat doubtful specimen of Astartella (apparently not A. nasuta Girty). A gastropod, apparently a species of Strobeus, completes the tale of the mollusks, and indeed of the entire fauna of this zone.—Girty manuscript.

From field relations, the sandstone tongue of the Cherry Canyon formation appears to be equivalent to beds between the base of the Cherry Canyon formation and the base of the Getaway limestone member toward the southeast. Its fauna should, therefore, be of about the same age as the sub-Getaway fauna, and should be a little older than the Getaway fauna. Dr. Girty, however, points out a number of marked differences between its fauna and that of the other two members. These differences are, perhaps, the result of differences in facies.

In the sandstone tongue, many genera and groups of brachiopods are absent or poorly represented, although they are well represented in the two faunas to the southeast. These faunas include the rhynchonellids and terebratuloids, and the genera Meekella, Chonetes, and Ambocoelia. Pelecypods and gastropods are likewise absent or poorly represented in the sandstone tongue, and are abundant to the southeast. Only one group of brachiopods—the orthoids—show any compensating increase in numbers; the genus Enteletes is common here, but is entirely missing to the southeast. Differences are not as striking among the productids and spiriferoids, so far as can be judged from the material collected; those of the sandstone tongue are found also to the southeast. The genus Leptodus also occurs in the same form in both areas.

GOAT SEEP LIMESTONE

Up to the time of the present investigation, no fossils had been described from the Goat Seep limestone of the southern Guadalupe Mountains. Some collections made by Darton and Reeside¹⁹ from Last Chance Canyon in the northern Guadalupe Mountains (fig. 2) had been identified by G. H. Girty. They are now known to be from beds of approximately the same age and facies as the Goat Seep.

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¹⁹Darton, N. H., and Reeside, J. B., Jr., Guadalupe group: Geol. Soc. America Bull., vol. 37, p. 426, 1926. "Fossils from above the unconformity."

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Even on the basis of the collections of the present investigation the fauna of the Goat Seep limestone is relatively poorly known. Fossils appear to be abundant in places, but are nearly all badly preserved on account of the prevailing dolomitization of the rock. Collections that have been made to date are therefore so few and widely scattered that they may not be representative of the fauna as a whole. The following report is based on six collections. Three are from the upper part, in the massive limestone facies, and were made on the summit of the range near Bartlett Peak (No. 7404) and in the northern Patterson Hills (Nos. 7482 and 7627) (pl. 2). Two others came from the basal beds on the west slope of the range (Nos. 7628 and 7646), and a third from the fossiliferous lens a mile north of Lost Peak on the east side of West Dog Canyon (No. 7603).

Nearly everywhere in the southern Guadalupe Mountains there are beds in the Goat Seep limestone that are crowded with fusulinids. Unfortunately, nearly all of these fusulinids are so dolomitized that the tests are preserved only as molds and show so few diagnostic characters, such as internal structure, that they cannot be identified. In the Last Chance Canyon area of the northern Guadalupe Mountains, from beds probably of the same age and facies, Skinner²⁰ has identified Parafusulina rothi Dunbar and Skinner and related species which occur also in the lower part of the equivalent Cherry Canyon formation in the southeast part of the area. From the Last Chance Canyon area Needham²¹ has identified Parafusulina dunbari Needham, which Dunbar and Skinner consider to be a synonym of their P. rothi (see p. 43).

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²⁰Skinner, J. W., letter, 1939.

²¹Needham, C. E., Some New Mexico Fusulinidae: New Mexico School Mines Bull. 14, p. 13, 1937.

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No cephalopods are known from the Goat Seep limestone, except some fragmentary specimens of "Orthoceras"

Dr. Girty's report on the remainder of the fauna is given below. This report gives no information on the occurrence of the forms cited at the individual localities, which is regrettable in view of the possible heterogeneity of the collections.

The collections include two sponges, one probably Guadalupia zitteliana Girty, the other of doubtful affinities, possibly a species of Amblysiphonella. Of corals, there are none, and of bryozoans, a doubtful species of Fistulipora.

Enteletes is present in one collection, and is not exactly rare. It probably belongs to E. liumbonus King. Some of the smaller but apparently mature specimens may be varietally distinct.

The Orthotetinae are fairly abundant and diversified, although the specimens themselves leave much to be desired. One species apparently belongs to Orthotetes distortus Girty. At one locality an uncommonly robust species of Meekella is abundantly represented by incomplete dorsal valves. It is identified as M. globose King. A smaller form is identified as M. skenoides Girty, and a single specimen which apparently belongs to this genus much resembles some of King's figures of M. irregularis texana King.

Chonetes is represented only by molds, which are so poor that they cannot be identified specifically.

Productids are fairly numerous, but are not varied. They occur mostly as molds or impressions, few of which are good, so the group is possibly more differentiated than it appears to be. With some reservations, I will cite: Productus guadalupensis Girty, P. (Cancrinella) a. sp. (apparently Avonia signata (Girty) as identified by King), a finely marked variety or possibly a distinct species related to the same, P. walcottianus Girty, P. popei Shumard?, and P. (Waagenoconcha) montpelierensis Girty.

A species of Aulosteges is abundant in one collection, and is the same as that which has already been cited several times as A. guadalupensis Shumard var. Prorichthofenia permiana (Shumard) is represented by a single specimen in one collection, and Teguliferina? sp. (which is possibly an immature Prorichthofenia) in another.

Rhynchonellids are scarce and only two species have been recognized. One is Rhynchopora taylori Girty, of which there is a single specimen. The other is a species that may be cited as Wellerella? swallowiana (Shumard)? and is rather abundant at one locality. Of the terebratuloids I have a single unidentifiable specimen of Dielasma and the generic position of that is open to question.

Spirifer occurs in but two collections, a large form with strong plications conspicuously grouped in fascicles of three, which may well be the species that King refers to as Spirifer pseudocameratus Girty. A single specimen of Spiriferina seems to be identical with S. billingsi Shumard.

Composita can be classed in two species, one C. emarginata affinis Girty, the other C. subtilita (Hall), or if not that species, at least one very close to it. A fragamentary specimen probably belongs to Hustedia and if so to H. meekana (Shumard).

Pelecypods are few, and for the most part poorly preserved. A large, subcircular Edumondia resembles E. circularis Walcott, and is probably the same species as one that is mentioned in the sub-Getaway fauna. Nucula is represented by a small, indeterminable specimen. A coarsely costate Parallelodon may be an imperfect and immature specimen of the new species mentioned several times in preceding faunas.

Pectenidae are better represented in numbers and variety than any other group of pelecypods, but most of the specimens are indeterminate or belong to undescribed species. One large and fairly well-preserved specimen appears to be a left valve of the species that was referred to Deltopecten vanvleeti Beede in the fauna of the Manzano group. Another left valve appears to be a species of Acanthopecten, possibly new. A small right valve may belong within one of the Guadalupian species of Camptonectes. Besides these specimens of more distinguishable species there are several too imperfect to be worth citing. An imperfect specimen of Myalina may well be M. permiana Swallow.

Of the scaphopods, a single specimen probably belongs to the species that I have been accustomed to identify as Plagioglypta canna White.

The gastropods can barely be identified generically, for the most part. The bellerophontids are represented by a few small specimens, but as they are internal molds it is impossible to tell the genus to which they belong. The pleurotomaroids are not represented at all.

A fragmentary internal mold probably represents a medium sized species of Naticopsis. Another specimen in a similar condition evidently belongs to a many-whorled, high-spired shell, possibly a species of Orthonema. Still another specimen must originally have had a spreading conical shape like Omphalotrochus or Euconospira.

The trilobites are represented by the persistent Anisopyge perannulata (Shumard)—Girty manuscript.

Comparisons with other faunas of middle Guadalupe age are made difficult by the scantiness of the collections from the Goat Seep limestone. On the whole, the Goat Seep fauna resembles that of the underlying sandstone tongue more than it does the Cherry Canyon faunas to the southeast.

Like the fauna in the sandstone tongue, this one contains few or no brachiopods of the genera Chonetes and Ambocoelia, or of the groups of terebratuloids and rhynchonelloids. All these brachiopods are present in the faunas to the southeast, and in some they are abundant. The last named group is common in the Getaway fauna, and is markedly developed in the South Wells fauna. Like the fauna of the sandstone tongue, and unlike the faunas to the southeast, Enteletes is present. The Goat Seep fauna, however, differs from that of the sandstone tongue and resembles those to the southeast in the abundance and fairly diverse character of the Orthotetinae (Orthotetes and Meekella). In the faunas both to the northwest and southeast, productids and spiriferoids are common, and appear to belong to the same general types, but collections from the Goat Seep and the sandstone tongue are too small to afford extensive comparisons with the faunas to the southeast.

Pelecypods and gastropods are better represented in the Goat Seep limestone than in the sandstone tongue, but are not as common as in the sub-Getaway and Getaway faunas. According to Girty:

Each fauna contains a number of genera and of species that are not known in some of the others, but many of the species are new, and more detailed study is needed before an accurate delimitation of genera and species can be presented. The pelecypod and gastropod faunas of the Goat Seep are evidently extensive, and many of the differences between its fauna and the others can doubtless be charged to the accidents of collecting.—Girty manuscript.

Comparison of the description of the Goat Seep fauna with descriptions of the Capitan and Carlsbad faunas that are given on later pages suggests that there are considerable differences between them. This fact is of interest because the two limestone formations of upper Guadalupe age overlie the Goat Seep and are of such similar rock facies that it is difficult to distinguish the one from the other two in the field.

CONDITIONS OF DEPOSITION

REGIONAL RELATIONS

During middle Guadalupe time, deposits were laid down not only in the Delaware Basin, but also in the shelf area beyond. As compared with lower Guadalupe time, the area of deposition was greatly increased (sec. c, pl. 7, B). The deposits both in and beyond the Delaware Basin were of marine origin. If the region outside the basin was land during lower Guadalupe time, there was a readvance of the sea during middle Guadalupe time. At first, the marine sediments laid down in both the basin and the shelf were sandstones, but before long the limestones of the Goat Seep began to be built up along the margin of the basin. Sandstone continued to be the dominant deposit in the basin, and was also laid down between limestone layers of the Goat Seep northwest of its margin.

In the Delaware Basin, deposits of middle Guadalupe age have a nearly constant thickness of 1,000 feet, whereas beyond the basin to the northwest their thickness is only 750 feet. Along the margin of the basin, they reach 1,500 feet, the increased thickness being mostly in the limestone layers of the Goat Seep (pl. 7, A).

It is not easy to restore the structure of the sea bottom on which these deposits of various thicknesses, and the similar ones of upper Guadalupe age, were laid down. The lay of the beds has since been modified, especially by the tilting and faulting that accompanied the uplift of the mountains during Cenozoic time. Reconstructions (such as those of pl. 7, B) have been made in part on the basis of the beds exposed on escarpments and canyon walls (some of which are shown on pl. 17), where the effects of later deformation are evident or unimportant. Further data on the reconstruction has been obtained from the thickness of the unit in different parts of the area, and from the nature of the beds found there.

The exposures shown in section K—K', plate 17, suggest that the great thickness of middle Guadalupe beds along the margin of the Delaware Basin was not accompanied by any local subsidence of the beds beneath, but rather that the thick deposits were laid down on a surface that sloped southeastward toward the basin. The section shows that the southeastward slope of the beds is steeper at the top than at the base of the unit, as though it had been accentuated during the period by greater deposition in the marginal area than in the basin. Less conclusive evidence from the exposures suggests, however, that there was no corresponding slope from the thick deposits of the marginal area towards the thinner deposits to the northwest; instead, the beds of the two areas appear to have joined in a nearly horizontal position (pl. 7, B).

These relations are explained by assuming that the Delaware Basin during middle Guadalupe time was a region of greater subsidence than the area outside it, and that the marginal area was consequently flexed down toward the basin in the same manner as it was during the formation of the older Bone Spring flexure but to a lesser degree. Under this assumption, sedimentation in the shelf and marginal areas kept pace more or less with subsidence, so where subsidence was moderate the deposits were thin, and where it was great the deposits were thick. The deposits are thinner within the basin itself than in the marginal area because sedimentation took place more slowly and thus did not keep pace with subsidence.

DEPOSITS OF THE DELAWARE BASIN

The source of the fine-grained sandstones of the Cherry Canyon formation is uncertain. Perhaps some of the material was derived from the south side of the basin, but here the equivalent beds, the Word formation of the Glass Mountains,²² contain much less clastic material than the formations that preceded them (fig. 14. A). Apparently the land that had previously contributed clastics to the south part of the basin was now contributing little sediment.

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²²King, P. B., Geology of the Glass Mountains, part 1: Texas Univ. Bull. 3038, pp. 69-73, 1931.

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On the other hand, sandstone does not appear to have moved freely into the basin from the northwest. The margin of the basin on this side was covered by limestone deposits of the Goat Seep, considerable thicknesses of which do not contain much sand. However, the limestones of the Goat Seep formation farther northwest are interbedded with sand that is coarser than any in the basin, and more like that which filled the basin in lower Guadalupe (Brushy Canyon) time. This coarser material was probably trapped behind the limestone barrier, and the finer material was able to make its way into the basin, either directly across the barrier, or through such openings in it as may have existed. This infiltration may have gone on slowly. At any rate, the possibility is suggested that sedimentation in the basin was so slow that it failed to keep pace with the subsidence taking place there. This condition was probably caused by the Goat Seep barrier.

The volcanic ash of the Manzanita limestone member, near the top of the Cherry Canyon formation, had a different source from the rest of the clastics and was no doubt the wind-borne product of distant eruptions. The eruptions probably were to the south, for near Las Delicias, Coahuila, a thick sequence of volcanic rocks is exposed, whose fossils indicate them to be of Leonard and Guadalupe age.²³ Further evidence that the source of the ash beds was to the south is given by Adams,²⁴ who states, on the basis of subsurface work, that in the region farther east bentonite layers in equivalent beds thicken southward. As there are some less-continuous ash beds both above and possibly below the Manzanita member, the volcanic activity in the distant region was probably long continued. Assuming that conditions of transportation and preservation were the same throughout Guadalupe time, the ash falls in Manzanita time were caused by an eruption more violent than the rest.

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²³King, R. E., The Permian of southwestern Coahuila, Mexico: Am. Jour. Sci., 5th ser., vol. 27, pp. 98-112, 1934.

²⁴Adams, J. E., Upper Permian stratigraphy of west Texas Permian basin: Am. Assoc. Petroleum Geologists Bull., vol. 19, p. 1016, 1935.

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Some of the sandstones of the Cherry Canyon formation were laid down in agitated water. In the lower half of the formation, many of them are cut by channels or marked by ripples. Channels are conspicuous along the southeast margin of the Goat Seep limestone mass.

The ripple marks in the sandstones, like those in the Brushy Canyon formation, have a general northeastward trend (fig. 8). In the Brushy Canyon formation, these ripple marks were explained as the result of wave motion or undertow currents oriented at right angles to the Bone Spring flexure, which was the shore at the time. In the Cherry Canyon formation, the shore lay much farther northwestward, but the Goat Seep limestone, whose southeast edge had a northeast trend similar to that of the flexure (fig. 8), apparently formed an area of shoals that probably had a similar influence on movements of the water. The channeling along the southeastern margin of the Goat Seep limestone is further evidence that it formed an obstruction to the waves. Most of the ripple marks in the Cherry Canyon formation are symmetrical, and were therefore formed directly by oscillation of the waves. A few asymmetrical ripples have been observed, however, whose steepest sides are to the southeast. These ripples were probably formed by undertow currents, moving away from the shoal water to the northwest.

Some of the limestone beds also appear to have been laid down in agitated water. Parts of the Getaway member contain pebbles eroded from the beds next beneath, and other parts contain fusulinids lying in parallel orientation, generally at right angles to the trends of ripples in adjacent beds. An environment of shallow, agitated water is suggested also by the rich and diversified bottom-dwelling fauna of the member. Similar pebble beds and oriented fusulinids are found in the gray, dolomitic limestones of the South Wells member along the northwest edge of the Delaware Basin. The irregular, lenticular development of the Getaway and South Wells limestone members suggest that they were laid down under disturbed conditions.

Some of the other beds of the Cherry Canyon formation were laid down in quieter water. The thin-bedded sandstones which form a large part of the sequence, with their thin, varvelike laminations, could not have been spread so evenly if the water had been much disturbed. Moreover, in the Getaway member, many of the bivalved shells are preserved entire, indicating that they had not been moved very far after the death of the animal. In fact, the bivalves may have been buried before the dead animal had decayed. Some of the beds are strongly bituminous, suggesting that from time to time the water was quiet enough to be fouled by decaying organic matter.

Bituminous limestones form a prominent part of the South Wells member in the southeast part of the area, away from the edge of the Delaware Basin. The fossils that they contain are less diverse than those in the Getaway member. The dominant group is the ammonoids, which were probably free-swimming organisms, whose shells settled into the fouled bottom water after death. The bottom-dwelling fauna is greatly reduced by comparison with that in the Getaway, except for rhynchonellid brachiopods. These brachiopods were probably more suited to inhospitable bottom conditions than other groups of animals. The Manzanita member also appears to have been laid down in quiet water, for its beds, including the volcanic ash layers, retain the same character and thickness over wide areas.

Indications of agitated water appear to be most common in the lower part of the Cherry Canyon formation, and of quiet water in the upper part. The channeling and ripple marking of the sandstones is found chiefly in the lower part. Likewise, the limestone beds in the upper part appear to have been laid down under quieter conditions than the limestone beds in the lower part. This change probably resulted from progressive deepening of the water during middle Guadalupe time.

FIGURE 8.—Map of area studied, showing distribution of facies and other stratigraphic features in beds of middle Guadalupe age (Cherry Canyon and Goat Seep formations). (click on image for a PDF version)

In parts of the Cherry Canyon formation, the beds tend to be repeated in cyclical order. The repetition of the cycle of shaly sandstone, sandstone, and nodular limestone below the Getaway member at one locality has already been noted (sec. 40, fig. 5). Higher up, each limestone bed or member is commonly underlain by massive sandstone and is succeeded by thin-bedded sandstone; this succession is repeated several times upward in the section (sec. 42b, fig; 5).

DEPOSITS OF MARGINAL AREA (REEF ZONE)

During the time when the Cherry Canyon formation was being deposited in the Delaware Basin, the limestones of the Goat Seep were being built up in the marginal area. As exposed in cross-section on the west face of the mountains, the limestone forms a solid mass only a few miles wide and interfingers northwestward as well as southeastward with sandstone. Although the mass is not widely exposed on either side of the mountain face, the evidence there suggests that it had the form of a reef that lay in a narrow belt trending northeastward (line B, fig. 8).

The bedding planes of the limestone indicate that at first the reef grew slowly as a series of broad, low lenses. Later on, when it formed massive beds, it grew more rapidly and became thicker than the deposits to the northwest or southeast. During the latter part of its growth as it was laid down on a southeastward sloping foundation it rose several hundred feet above the floor of the Delaware Basin to the southeast. During this time, as already indicated, the deposits in the basin were laid down in less agitated (and perhaps deeper) water than the earlier deposits.

Like the other limestones along the margin of the Delaware Basin the Goat Seep limestone is quite generally dolomitized, with the result that many of the details of its original structure are now lost. Not many reef-building organisms have been collected from it. No corals have been found, but Dr. Girty reports the presence of sponges. It is not possible, therefore, to determine whether the Goat Seep reef was built by organic or by inorganic growth. By analogy with the succeeding similar Capitan limestone, organisms probably aided materially in its construction.

The margin of the Delaware Basin, where the bottom sloped down from the shallow shelf area into the deeper, more rapidly subsiding area of the basin, must have been a favorable place for such organisms to grow and to build up masses of limestone. The margin would be favorable also for direct precipitation of calcium carbonate, for water that moved into the warm, agitated shallows from the deeper, quieter, and perhaps cooler waters of the basin probably lost its dissolved carbon dioxide and thus became supersaturated with calcium carbonate.