Geological Survey Bulletin 614 Guidebook of the Western United States: Part D. The Shasta Route and Coast Line

MEDFORD TO WEED VIA CRATER LAKE.

The distance from Medford to Crater Lake by automobile stage is 79 miles. The first 20 miles lies through orchards, mainly of apples and pears, over gravel plains spread out by the streams as they issue from the mountains, and through foothills where the sandstones and shales (Eocene to Miocene) of the valley dip eastward under the lava flows of the Cascade Range.

At 31 miles from Medford the road crosses Rogue River, and thence for 16 miles, to the mouth of Mill Creek, it follows the north bank of the river through a deep canyon. From the roadway may be had good views both of the canyon and the uplands bordering the wider valley to the west.

Near Prospect (elevation 2,780 feet) Rogue River is again crossed at the head of its canyon. Here the river in a quarter of a mile falls 325 feet in a series of cascades, at the foot of which Mill Creek, in a fall of great beauty, 150 feet in height, joins Rogue River. Near Prospect the primeval forest begins, and for miles the smooth road built on terraces of lava affords fine forest views.

At Union Creek, 58 miles from Medford (elevation about 3,500 feet), there is a delightful camping place near Natural Bridge and Union Falls. The Union Falls are really cascades over some black lava (basalt), and there are similar cascades at Natural Bridge, a little farther downstream. These cascades came into existence in the following way. In late geologic time (Quaternary) a lava flow came down the bed of Rogue River with scant regard for previous water rights. When the lava had reached a point about a quarter of a mile below Natural Bridge it cooled and stiffened sufficiently to stop. The basalt still shows the ropy forms in which it congealed and the bubble cavities or vesicles formed by the steam that nearly all lava contains. Shortly afterward a second stream of lava came down on top of the first but did not run quite so far. The river now reoccupied its bed as well as it could and at first cascaded over the ends of the lava flows. In course of time it wore back gorges, 60 feet deep, in the basalt, and it is still busy at the same task. At Natural Bridge the stream has discovered and doubtless enlarged an old tunnel such as is often formed in lava streams by the continued flowing of the deeper molten material after a solid crust has formed above it.

Ten miles beyond Union Falls is the entrance to Crater Lake National Park. The lake is deeply set in the crest of the Cascade Range, the surface of the water being at an altitude of 6,177 feet. It is encircled by a cliff from 500 to nearly 2,000 feet high. From the top of this cliff the ground slopes away gently on all sides, so that the lake partly fills a great cup or pit in the summit of a broad conical mountain. This comparatively low mountain is all that remains of a once mighty volcano, Mount Mazama (Pl. XVII, A). In all probability no human eye ever looked upon this peak, but geologists know that it existed and that glaciers crept down its flanks and gouged out its canyons. Through some cause unknown this mountain collapsed—its top fell in, leaving the hole now occupied in part by the lake, 2,000 feet deep.

PLATE XVII.—A. MOUNT MAZAMA RESTORED. As it appeared before it collapsed to make the great pit now half filled by Crater Lake, which is nearly 2,000 feet deep. B. WIZARD ISLAND, CRATER LAKE, OREG. A small volcano (cinder cone) that has grows up in the great pit formed by the coliapse of Mount Mazama. Across the lake is Llao Rock, formed by a lava flow from Mount Mazama that now fills a little valley in the rim of the crater.

Wizard Island (Pl. XVII, B) is a small volcanic cone built up from the bottom of the pit and now probably extinct. From it may be had superb views of the cliffs that surround the lake. The sky line of these cliffs shows U-shaped notches (Pl. XVIII, p. 54), which are sections of the glaciated valleys that formerly headed high up on Mount Mazama.

PLATE XVIII.—SOUTHEAST RIM OF CRATER LAKE, OREG. FROM WIZARD ISLAND. Shows U-shaped valleys cut by the glaciers of Mount Mazama. Photograph by Kiser Photograph Co.

From Crater Lake Lodge, situated on the rim 1,000 feet above the lake, excursions may be made to many places of interest, especially the glaciated valleys of Sun and Sand creeks, the great pumice-covered flow of Llao Rock, and the latest lava flow of all, at Rugged Crest. A trip by boat to Wizard Island and around the lake gives the visitor an opportunity to fish and to see the materials of which the great volcanic cone was built and the way in which these have been piled up in successive layers.

From the lake to Chiloquin, a station on the Southern Pacific Co.'s new line from Weed, Cal., via Klamath Falls, the distance is 35 miles. This new line is intended when complete to be the main line between Weed and Eugene, Oreg. From the lake to Klamath Falls by the automobile road the distance is 65 miles. From the point where the road leaves Crater Lake the view over the broad platform of the Cascade Range (Pl. XIX, p. 55) includes the great cones of Shasta and Pitt, with many others, large and small, each once an active volcano.

PLATE XIX.—SUMMIT OF CASCADE RANGE. Looking south from the rim of Crater Lake, Oreg. The summit of this range is a plateau studded with volcanic cones. Union Peak near the center; Mount McLoughlin on the left in the distance. Photograph by Kiser Photograph Co.

The descent from the rim of Crater Lake is at first very steep over a moraine (the bowldery deposit left in front of a glacier) to the great spring at the head of Anna Creek. The road affords fine views of the canyon of Anna Creek, cut deep in volcanic ejecta. Near its head the rocks have been eroded into cigar-shaped pinnacles and farther down systems of parallel cracks in the rocks (jointing) give striking columnar effects. On the east, across Anna Canyon, stands Crater Peak (7,265 feet), one of the outlying basalt cones built up on top of the flows of andesite that made the bulk of Mount Mazama. After flowing through some finely forested, gently sloping country Anna Creek enters upon the broad alluvial plain of upper Klamath Lake.

Fort Klamath, on the western border of the Klamath Indian Reservation, is now only a small village but was an active Army post at the time when military force was necessary to keep the Indians in order. Several of the old fort buildings are still standing. Here it was that the notorious chief known as Captain Jack was tried and hanged for the part he played in the Modoc war, the scene of which was among the lava beds about 60 miles southeast of Fort Klamath. The Klamath Indian Reservation contains much fine pasture and farm land, as well as forest, and many of the Indians are engaged in agriculture. A few miles from the fort are the well-kept buildings of the Klamath Indian Agency.

Wood River, the clear, cold stream that supplies the fort and agency with water, rises on a fault whose course is marked by a prominent bluff leading up toward Crater Lake. The water of the river may possibly be derived in part from the lake by underground flow along the fault fissure.

Five miles beyond the agency is Chiloquin, a small village on Williamson River. The water of Williamson River, though clear, has the brown color characteristic of streams that drain swamps. This river is noted for its trout, but the Sprague, into which it empties half a mile below Chiloquin, is turbid and contributes to the muddiness of upper Klamath Lake.

At the crossing of Sprague River an excavation for a ditch reveals bright-colored lake beds, which evidently underlie the soil of the plain. Modoc Point, on the northeast side of Upper Klamath Lake, is part of a bold bluff of dark lava (basalt) lapped by the waters of the lake. The bluff marks the course of a northwesterly crack along which the rocks on the southwest side have sunk or those on the northeast side have risen—in other words, the lavas are faulted. The bluff is part of the southwest edge of a block of the earth's crust that has been tilted toward the northeast. The effect of the fault has been to form the hollow, deepest on the northeast and shoaling to the southwest, in which the lake lies. There are other faults of the same kind and general direction in southeastern Oregon, and a number of these have produced lake basins.

From Modoc Point Mount Pitt (9,760 feet) may be seen by looking west across Pelican Bay. To the south, across the main lake, appears the snowy peak of Shasta (14,350 feet).

The Plum Hills, near Algoma station, have been carved by erosion from an uptilted fault block such as has just been described. The fault fissure runs along the west base of the hills. Dipping east under the lava which forms the upper part of the hills are some fine, thin-layered beds which were deposited in a lake that existed before the lava was erupted.

Klamath Falls (elevation 4,120 feet), at the outlet of Upper Klamath Lake, is a thriving town, to whose growth the new through line of the Southern Pacific, now under construction, and the great Klamath reclamation project of the Government have given added impetus. The Klamath Basin, which lies partly in California and partly in Oregon, embraces several thousand acres. Much of the land to be reclaimed and irrigated was covered by lakes and marshes, but the waters are being drained off and the land, divided into farms, is being irrigated by the Government canals. About 30,000 acres are now under irrigation, and when the system is completed it will include 72,000 acres of irrigable land. Practically all the uplands, which comprise the greater part of the area, are privately owned, a portion being in large holdings which, under the terms of the reclamation act, must be subdivided into tracts of not more than 160 acres and sold to actual settlers. The public lands, including much of the lake areas, are at present withdrawn from entry but will later be opened to homestead entry.

Beyond Klamath Falls the railroad crosses a great area of tule (too'lay, the Spanish name for a species of rush (Scirpus lacustris) common on the swamp lands of the Pacific coast). The reclamation of this area is part of the Government project. On the right is Klamath River, and beyond is the gap in the Cascade Range through which the river makes its way. A flow of comparatively recent lava in the gap has formed a dam which by ponding back the river has contributed to the formation of the lakes and swamps of the country now being traversed.

At Midland, among the marshes, the traveler enters a national bird reserve, where ducks, geese, and many other waterfowl are abundant and are secure from molestation. Near Worden, which lies among low lava hills, apple orchards and fields of grain appear as if by magic, surrounded by sagebrush and cedars.

By several tunnels through ridges composed of bright-colored beds of tuff (lava particles thrown out by the explosive action of volcanoes) Doris (elevation 4,238 feet) is reached. Beyond it are other small towns surrounded by hay and grain fields. The hills become better wooded as the Cascade Range is approached. The eastern front of the range, as seen from Macdoel (elevation 4,256 feet) and Mount Hebron (4,237 feet), is so abrupt as to suggest that this part of the range may have been uplifted above the country to the east by a fault. The region about Mount Hebron is a fine cattle country. Forests become more conspicuous at Jerome, where the railroad crosses a low divide between the drainage basins of Butte Creek and Little Shasta River.

At Kegg there is some well-stratified dark volcanic material that is widely used for railroad ballast. This material, somewhat resembling cinders, was blown out from some volcano. Such fragments of cindery lava are known as lapilli (little stones). The rich green pastures of the small valleys of this part of the route are bright with flowers and dotted with contented cattle. They are surrounded by dark forests of yellow pine (Pinus ponderosa), which is now being extensively cut for lumber.

From Bray (elevation 4,648 feet) may be seen Goose Nest Mountain (see sheet 8, p. 64), on the right (west), directly across the valley. Another low divide (5,078 feet) is crossed, and Grass Lake, surrounded by swampy pastures of green and yellow grass, comes into view. This country drains westward through Little Shasta River to Shasta Valley. From Pineland the road descends toward Mount Shasta, with the rugged cliffs of Sheep Rock on the right. These cliffs are composed of dark lavas and tuffs, which dip east.

Mount Shasta continues in sight for many miles. The most impressive view is obtained from the station called Mount Shasta. The mountain has two summits. The higher one, on the left (14,380 feet), is that of Mount Shasta proper; the lower one (12,433 feet) is Shastina. Whitney Glacier lies between the two peaks and is over 2 miles long. A prominent gray pile of bowlders and gravel, clearly in view at the lower end of the glacier, is its terminal moraine. Mount Shasta above a level of 4,000 feet is composed of lava, chiefly a kind containing less silica and generally lighter in color than basalt, known as andesite. There are a few basalt cones about the base of the mountain. Near milepost 364 are some light-gray hills known as the Haystacks, composed of sedimentary and intrusive rocks like those of the Klamath Mountains and forming, as it were, an island in the sea of lava.

About 5 miles beyond the Haystacks, on the right, is a steep little valley formed by a caved-in lava tunnel. When the supply of lava is cut off at the close of an eruption the molten interior of a flow continues to move down hill under its hardened crust; leaving tunnel-like caves which may be a mile or more long.

Beyond this valley is a gravel deposit made by Whitney Creek, which is fed by Whitney Glacier. The creek has cut a deep canyon for several miles below the glacier, but before it reaches the point where the railroad crosses it the stream becomes overloaded with gravel and has to drop part of its load. In summer the creek disappears in the porous gravel deposit.

The flows of lava that once poured down the sides of Mount Shasta end in bluffs around which the railroad swings to Weed.