Geological Survey Bulletin 612 Guidebook of the Western United States: Part B

Elkhorn is the first station west of the Lane cut-off and is located on one of the branches of Papillion Creek. East of this station the railroad crosses the eastern margin of the widespread Dakota sandstone, but the rock is so completely covered by glacial drift and loess that in no place can it be seen from the train and, indeed, its exact position is not known.

FIGURE 3.—Cross section of the rock formations from the Rocky Mountains to Omaha, Nebr., showing how some of the older rocks that crop out near Omaha extend westward underneath the younger formations and crop out again in the mountains, where all the stratified rocks have been upturned and eroded. (After N. H. Darton.)

At Waterloo the railroad crosses Elkhorn River, which, unlike most other streams, does not here flow in a valley of its own making but for 25 miles or more meanders over the bottom lands of the Platte.

Between Elkhorn and Waterloo great differences are noticeable both in the character of the surface and in the soil. To the east the surface is diversified by low rolling hills and broad shallow valleys completely mantled with loess. The loess forms a fairly good soil, but its inferiority to the dark-colored loam of the bottom lands is obvious to the most casual observer of the vegetation. West of the hills, in Platte Valley, the surface is flat and unbroken and the soil is more productive. (See Pl. III, p. 11.)

PLATE III.—THE PLAINS OF NEBRASKA. Top to bottom: A, Fifty years ago; B, Now covered with corn; C, When buffalo roamed over them; D, Supporting herds of domestic cattle. Photographs furnished by Union Pacific Railroad Co.

Valley is the center of an agricultural district in the rich bottom lands of Platte Valley. Large quantities of garden seeds are grown here. About 3 miles west of Valley the traveler will obtain his first good view of Platte River. The railroad follows this river as far upstream as Julesburg, in northeastern Colorado, a distance of about 350 miles.

Although Fremont, the seat of Dodge County, is on the flood plain of Platte Valley, where few exposures of rock can be seen, it stands near the contact of the Dakota sandstone and the overlying Benton shale, a fact determined by observations made both north and south of the valley. The sandstone¹ may be seen in the bluffs at the south end of the wagon bridge south of the city, but the shale is not exposed. These bluffs consist mainly of glacial till mantled by loess.

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¹The rocks in eastern Nebraska referred to the Dakota or basal sandstone of the Upper Cretaceous series are about 300 feet thick and consist of sand with clay and local beds of conglomerate. The sandstone was named for Dakota City, S. Dak., where collections were made of fossil plants that were described by Profs. Heer and Lesquereux and later became known as the characteristic Dakota flora, for many years the oldest deciduous-leaved flora known in North America. This flora comprises large and well-preserved leaves of poplars, willows, oaks, alders, birches, beeches, sycamores, persimmons, tulip trees, magnolias, and sassafras and shows that many of the familiar and still dominant types of plants had already been firmly established at this remote time. However, none of the particular species of Dakota plants here discovered are known to have survived in this region beyond the close of the Dakota epoch.

The Dakota is exposed in places in the bluffs of Platte River from Fremont to Plattsmouth. It is one of the greatest water-bearing formations in America. It rises gently toward the west, although covered by younger rocks, and crops out again in the foothills of the Rocky Mountains (see fig. 3), where the surface waters enter it. These waters slowly percolate through its sands for about 450 miles to supply the numerous wells in the Platte Valley and elsewhere. The Dakota sandstone extends 400 miles or more north of the Union Pacific Railroad and an equal distance to the south and underlies the surface of the country from the Rocky Mountains eastward to a maximum distance of 1,000 miles or more. It furnishes excellent water to the citizens of 11 States.

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Fremont is on the main line of the old trail from Missouri River to California and Oregon, which before the Union Pacific was built was known as the Overland Trail.² In front of the station stands a rough-hewn monument of red granite with the inscription: "This boulder marks the overland emigrant trails though Fremont to Oregon, California, Utah, and Colorado. Erected September 23, 1912, by Lewis Clark Chapter, Daughters of the American Revolution." Similar monuments have been placed at many other railroad stations on the line of the old trail.

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²Although four transcontinental railroad routes were surveyed by the Government, the results being published in 11 large volumes, the first line built, the Union Pacific, was explored and located by private enterprise. The Overland Trail seemed to offer the best advantages for railroad construction, inasmuch as it utilized the most feasible passage over the mountains. Gen. Grenville M. Dodge, the chief engineer of the Union Pacific during the period of construction, says of it: "This route was made by the buffalo, next used by the Indians, then by the fur traders, next by the Mormons, and then by the overland immigrants to California and Oregon. It was known as the great Platte Valley route. On this trail, or close to it, were built the Union and Central Pacific railroads to California and the Oregon Short Line branch of the Union Pacific to Oregon." Its history as a definite route seems to have begun in 1804, when Lewis and Clark visited and described the locality that became its eastern terminus. A fur-trading company sent out by John Jacob Astor in 1810, which founded Astoria, Oreg., at the mouth of Columbia River, the following year, returned by a route which had never before been traversed, but which corresponded essentially with that later known as the Oregon Trail. Astor had planned a line of trading posts extending from the Great Lakes to the Pacific, the Sandwich Islands, and China, but the War of 1812 put a stop to this scheme. About 1824 William H. Ashley and Etienne Provost, of the Rocky Mountain Fur Trading Co., discovered South Pass, which made permanent the mountain-crossing route of the Oregon Trail and later attracted the Union Pacific locating parties. Gen. Dodge says further:

"In 1843 the pathfinder, Gen. John C. Fremont, began to spy out the military ways across the West, and the same year the Oregon pioneers took the first wagons westward to the Pacific. The trail that began with the journey of these early pioneers was widened and deepened by the wheels of the Mormons in 1847, and when the herald of the first California Golden Age sent forth a trumpet call in 1849, heard around the world, the trail was finished from Great Salt Lake across the mountains to the sea.

"That era had its great men, for great men make eras. Ben Holladay, William N. Russell, and Edward Creighton gave to the trail the overland stage line, the pony express, and the telegraph.

"Dating the beginning of transcontinental wagon travel from the days of forty-nine, it was 20 years before the railroad reached California. The period was one of great out of door men and women—the last of American pioneers. When the old trail was in full tide of life it was filled with gold seekers from the Missouri to the Pacific; 100,000 travelers passed over it yearly. Towns stirring and turbulent, some now gone from the map and some grown to be cities, flourished as the green bay tree. Omaha, Salt Lake, San Francisco and such lesser places as Julesburg, Cheyenne, Laramie, Carson, Elko, and Virginia City were picturesquely lively.

"The traffic of the old trail was of long wagon trains of immigrants; the great outfits laden with freight for the mines; of Holladay's coaches, six teams in full gallop; of the first riders of the pony express; and of all other manner of moving men and beasts. The protesting savages have no place upon it but, perceiving in it an instrument to alienate their domain, burned its wagon trains and destroyed its stages as opportunity offered. At times great herds of buffalo obliterated great sections of the trail, yet it held its own until the golden spike was driven and passed away as a wagon road only when the need for it had passed. But the railroad lines that took up the burden of stage coach and pony express and ox team have marked the way of the trail upon the map of the West so that it shall endure as long as the West endures."

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From Ames may be seen a gap in the line of bluffs south of Platte River that marks the course of an old valley occupied by the river at an early stage of its development, when its bed was about 100 feet higher than at present. The river then flowed southeastward past Wahoo and thence eastward to the valley which it now occupies south of Waterloo. This old channel is 5 or 6 miles wide and consists of a valley floor covered with loam and sand like the floor of the present valley. Also like the present valley it is bordered along most of its course by steep banks of loess.

The town of North Bend (see sheet 2, p. 22) takes its name from the northward bend of Platte River at this point, west of which the railroad follows the river in a southwesterly direction for a long distance. South of the river, opposite North Bend, the bluffs are conspicuous, especially west of Morse Bluff, and consist of loess and glacial drift overlying shale of Benton (Cretaceous) age.¹ This shale was formed as a mud deposit at a time when Nebraska was at the bottom of a sea. It contains many fossil shells of extinct species of marine mollusks, such as oysters (see Pl. IV, A, B, p. 20), clams, and snails, as well as many fossils of types not represented by living forms, such as ammonites and scaphites. It underlies the superficial glacial deposits between Fremont and a point a few miles west of Schuyler.

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¹The Benton shale lies conformably on the Dakota sandstone, that is, the beds of the Dakota were not affected by erosion before those of the Benton were laid down upon them. In Nebraska and some other areas a thin limestone (Greenhorn) near the middle of the Benton separates a lower shale (Graneros) from an upper shale (Carlile). The lowest beds crop out near Fremont, where the Dakota passes underneath it not to reappear at the surface again toward the west for a distance of about 450 miles. It is a marine shale representing the first deposits formed after the sea invaded the interior of North America in the Upper Cretaceous epoch.

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PLATE IV.—MARINE FOSSILS OF CRETACEOUS AGE. A (top, left), Oysters (Ostrea congesta); B (top, right), Inoceramus labiatus; CARBONIFEROUS FOREST. C (bottom). From vegetation of this sort the great deposits of coal were formed.