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

SHEET No. 15C. (click on image for an enlargement in a new window)

At Tyhee (see sheet 15C, p. 138), 1-1/2 miles south of the Fort Hall Indian Reservation, the railroad turns more to the north and a view is obtained on the left of the middle and east buttes of the three already mentioned. The sagebrush flat now being crossed is owned by the Indians. Very little land has been cultivated in this part of the reservation, although much of the land is under ditches of the irrigation system installed by the Government. Near Tyhee may be seen the large upper canal which takes water from Blackfoot River about 15 miles to the north. The canal is carried under the track near Tyhee by means of an inverted siphon.

East and northeast of Tyhee the old flood plain of Snake River terminates against a bluff about 40 feet high, from the top of which the land rises gently in long slopes to the hills made of upturned Paleozoic rocks, more or less covered with lava. The gently sloping bench lands are themselves composed of marls, sandstone, conglomerate, volcanic ash, and lavas. These deposits are geologically very young, probably Pliocene. They cloak the older formations over many square miles.

Three gray stone buildings with red roofs east of the track belong to a boarding school for Indian boys and girls, where the 180 pupils are given instruction in practical matters relating to farm life as well as the ordinary academic courses.

Fort Hall is the headquarters of the superintendent of the Fort Hall Indian Reservation and the engineers on the reclamation project. The Indian women seen here are dressed in blanket and moccasins, and the men in semicivilized costume. Some of the Indian maidens, however, wear gowns of the latest styles. Fort Hall, formerly called Ross Fork, from the stream on which it is built, takes its present name from a fort which was built in July, 1834, about 15 miles to the northeast, at the junction of the Missouri-Oregon and Utah-Canada trails, by Capt. N. J. Wyeth and named for one of his partners. It was to the original fort that Dr. and Mrs. Marcus Whitman and Rev. and Mrs. H. H. Spaulding came in 1836 on their way from Boston to missionary labors among the Indians in Oregon. Theirs were the first wagons and Mrs. Whitman and Mrs. Spaulding the first white women to cross the, Rocky Mountains. The party forded Snake River near the site of Blackfoot and went bravely west over the waterless plain. The old fort was abandoned many years ago and practically all vestige of it is lost.

In the Fort Hall Reservation sagebrush seems to cover every acre and the traveler may question if the Indians cultivate any land. Most of the Indians, however, live near the creeks and their homes can not be seen from the train. In 1914 they had 7,240 acres under cultivation. The principal crops are alfalfa, oats, wheat, potatoes, barley, garden truck, and sugar beets. According to the report of the Commissioner of Indian Affairs for 1914 the total Indian population of the reservation was 1,797, including 462 children of school age. Of these Indians, 1,506 are full bloods belonging to the Bannock and Shoshoni tribes. There had been allotted to the Indians 38,280 acres of irrigated land and 330,971 acres of grazing land. The old and decrepit Indians, 250 in number, get rations. More than two-thirds of the Indians live in tepees and tents. Nearly a third of them winter on the Snake River bottoms, where there is timber for shelter, fire wood, and plenty of pasturage and where snow rarely lies more than a few days.

The road up Ross Fork from Fort Hall station leads across the mountains to the dam of the great Blackfoot reservoir, about 30 miles east, built to store water for the Fort Hall irrigation system. Phosphate deposits occur about 20 miles east of Fort Hall station along this road. The deposits in this reservation contain approximately 738,000,000 long tons and are estimated to underlie 58-1/2 square miles at depths of less than 5,000 feet; they doubtless underlie a much larger area at greater depths. The main phosphate bed is 6 or 7 feet thick and is rich in tricalcic phosphate, the mineral constituent in bones. The phosphate beds are relatively soft and are exposed in only a few places, although clearly recognizable fragments of phosphate rock are scattered more or less abundantly along the zone of outcrop. A description of the western phosphate field, by G. R. Mansfield, is given below.¹

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¹A hard problem for the farmer is to discover the needs of his depleted or unfavorably proportioned soil. Its greatest need may be phosphoric acid, one of the three substances that are most necessary in maintaining fertility, the other two being nitrogen and potash. Phosphoric acid for use in fertilizers has been supplied for many years in part by the phosphates of Florida and Tennessee and from islands in the Pacific Ocean. These deposits can not always supply the demand, and therefore the recent discovery that the Rocky Mountains contain the largest known area of phosphate rock in the world is of vital interest to future generations, if not to the present one.

Albert Richter claims to be the original discoverer of the western phosphate deposits, because he recognized rock phosphate in Cache County, Utah, in 1889 and located claims on it. These phosphate deposits are said to have been independently discovered in 1897 by R. A. Pidcock in Rich County, Utah, in old diggings in black rock that he mistook for gold prospects. A large sample analyzed in 1899, however, proved to be high-grade phosphate rock. In 1908, on recommendation of the Geological Survey, Secretary of the Interior Garfield withdrew from entry 4,500,000 acres of public land in Idaho, Utah, and Wyoming believed to be valuable for phosphate, and this phosphate withdrawal was continued by President Taft under the act of June 25, 1910. In 1909 and succeeding years these phosphate deposits were systematically examined by the United States Geological Survey, and in 1910 phosphate rock was discovered in Montana, near Melrose, by Geologist H. S. Gale. On January 1, 1915, the total area of phosphate lands in Montana, Utah, Wyoming, and Idaho withdrawn from entry was 2,713,155 acres, This phosphate reserve is larger than any similar area in the United States; it is, indeed, the largest area of phosphate rock yet recognized in the world.

A characteristic of the phosphate rock of this region is its oolitic texture, the rounded grains, resembling fish eggs, ranging in size from the tiniest specks to bodies half an inch or more in diameter. In its weathered condition these grains are more or less distinct and the rock has a grayish color. When freshly mined, however, the rock is dark brown or black. In some places where the rock has been subjected to great compression during the deformation of the inclosing strata it has apparently lost the oolitic texture and shows a slight increase in density.

The phosphate deposits in the West occur in definite beds that extend over wide areas and that are related to the associated rocks in the same way as coal beds. The associated beds are predominantly shaly, but include also sandstones and limestones, the whole ranging in thickness from a few feet to 175 feet. Above these phosphate shales there is commonly massive chert or cherty limestone, and below them in the Utah, Wyoming, and Idaho fields a light-colored siliceous limestone. These three sets of beds in Utah and western Wyoming are grouped together as the Park City formation, of Carboniferous age. In Idaho the phosphate shales and overlying chert are called the Phosphoria formation. The number of phosphate beds distributed through the phosphate shales varies from place to place. There is, however, usually near the base, a bed 5 or 6 feet thick in the Idaho field and the adjacent portions of Wyoming and Utah. This bed is also of uniformly high quality, averaging 32 per cent or more of phosphoric acid, equivalent to 70 per cent or more of bone phosphate. The total quantity of high-grade rock in this main bed, estimated for the areas examined by the Geological Survey in five years (not including Montana fields), is approximately 5,000,000,000 long tons. This estimate includes only rock that is believed to lie at minable depths—that is, less than 5,000 feet from the surface—but does not include a vastly greater quantity of lower grade rock.

The raw phosphate rock is not readily soluble, so that its action in fertilizing land is very slow, but the so-called super-phosphate, made by treating the pulverized rock with sulphuric acid, which the smelters of the West can furnish in large quantity, contains phosphate in more easily soluble and available form. At present, on account of the cost of transportation to the eastern markets, the demand for western phosphate is confined to the Pacific Coast States, and even here it is in competition with phosphate rock imported from Ocean Island. Of the total phosphate rock produced in the United States in 1914, the Western States furnished less than one-half of 1 per cent. With the growing recognition of the importance of intensive agriculture and the consequent need of fertilizers in the great agricultural districts that have passed the period of maximum fertility, the demand for phosphate rock is certain to increase. Although at present the deposits in the Eastern States are more accessible to markets, these deposits are already approaching partial exhaustion, so that this rich and extensive western field, already important as a grazing district, is destined to become the scene of another thriving industry.

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North of Fort Hall station, 1 to 3 miles east of the track, there is a group of low rounded hills composed largely of basalt lava but covered for the most part with dark sand that was blown out from a volcano, the basalt appearing here and there as ledges and bowlders of black rock. From Fort Hall station an excellent view may be obtained of the highest mountains in the reservation, North and South Putnam situated 15 to 18 miles to the southeast and reaching 8,837 and 8,989 feet, respectively, above sea level.

North and west of Fort Hall station the surface of the flat is overspread with dark sand, largely of volcanic origin. It is similar to volcanic ash except that it is coarser. This sand is piled in low dunes west of Fort Hall, and some of the dunes have been utilized as burial places by the Indians. These Indian cemeteries are marked by high poles, set rather close together, which may be seen for considerable distances. A cemetery about 2 miles west of the track and 1 mile north of Fort Hall can be seen from the train in clear weather. On close inspection the cemeteries are found to be decorated with effects of the departed Indians, including clothing, cooking utensils, and implements.

Volcanic hills, composed largely of a rhyolite lava, appear to the east at a distance of 4 or 5 miles from Gibson siding. On one of the nearer hills of this group there is a very symmetrical little cone built of material similar to that which makes so large a proportion of the dark volcanic sand found abundantly in this vicinity. It seems probable that this little cone is the crater from which the sand was blown out and that its eruption marks perhaps the latest chapter in the volcanic history of the district.

For many miles north from Fort Hall the three buttes in the Snake River plain are visible in clear weather. The westernmost, or Big Butte, is an old volcano rising 2,350 feet above the plain, or 7,659 feet above sea level. East Butte, also a volcano, is 700 feet high, and Middle Butte, an upraised block of basaltic lavas, is 400 feet high. Big and East buttes are ancient rhyolitic volcanoes which existed previous to the outpouring of the fluid basalt that flowed about them, their upper parts rising as islands in this sea of molten rock. They are about 25 and 35 miles from Blackfoot, and Big Butte is 15 miles from Middle Butte and 20 miles from East Butte. The Lost River and Lemhi ranges may be seen behind the buttes.

North of Gibson there may be a few tepees along the road. At the south end of the bridge over Blackfoot River there is a well-appointed ranch, the home of a prosperous Indian who owns an automobile and has several hundred head of horses and cattle in the hills.

Blackfoot River,¹ which the railroad crosses 1 mile south of the village of Blackfoot, is the north boundary of the Fort Hall Indian Reservation.

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¹The mean discharge of Blackfoot River in 1906-1909, measured at Presto, a few miles upstream from the railroad, was 415 cubic feet a second. It has a recorded range from a maximum of 2,370 to a minimum of 64 cubic feet a second during that period. No hydroelectric power plants are in operation or in process of construction on this stream. Although the fall of the river from the Blackfoot dam down to the mouth of the canyon is comparatively great, the storage of water for irrigation makes it impracticable to develop any very large amount of continuous power. Besides the 48,000 acres to be irrigated on the Fort Hall Reservation, 6,000 to 10,000 acres are irrigated by independent or private ditches taking water from the river.

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Blackfoot city and river are named from a tribe of North American Indians. The name is explained as an allusion to an observation by pioneer whites that their leggins were generally blackened by walking over the freshly burned prairie. The Indians commonly seen about the station and on the streets, however, belong to the Lemhi, Bannock, or Shoshone tribes. Blackfoot is the business center of a large, well-settled, and prosperous irrigated agricultural district, and is sometimes called the "grove city," because all the streets in the residence section are well lined with mature shade trees. It is noteworthy that the first trees ever planted in upper Snake River valley were set out around the Blackfoot courthouse in 1886, and a ditch was constructed for irrigating them. Three grain elevators and a flour mill suggest that a large part of the produce of the surrounding district is grain. The railroad station, one of the finest on the line, is built of pink rhyolite, a lava rock that is abundant in the hills to the east. Blackfoot is the junction point for branch lines to Mackay and Aberdeen. Gasoline motor trains are run on these lines and also to Pocatello. The city water supply is pumped from wells drilled to depths of 120 to 150 feet, which reach basalt (black lava) at 65 feet. These wells show the depth of sand and gravel deposited at this place by Snake and Blackfoot rivers in wandering about over the surface before settling in their present courses.

The electricity used in Blackfoot is brought from a power plant on Snake River at American Falls, 40 miles to the southwest.² Gold placers on Snake River about 15 miles below Blackfoot have been worked intermittently in former years, but are now idle. In hard times a few men wash out a little gold by panning, but here, as elsewhere on Snake River, the gold is so flaky and fine that it is difficult to recover. Several attempts at large operations with dredges have been failures. A beet-sugar factory at Blackfoot, built in 1905 at a cost of $500,000, contracts for the beets from about 7,000 acres and pays $5 a ton for them. The average yield is about 12 tons to the acre, but some tracts under skillful treatment produce 20 to 22 tons.

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²The mean discharge of Snake River at Blackfoot during 1911-1914 was 7,930 cubic feet a second.

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The flat extending from Snake River, 3 miles west of the railroad, to the foot of the hills on the east is all under irrigation ditches, practically every acre being cultivated. The agricultural interests of this valley are diversified; no one crop predominates. On either side of the track are fields of alfalfa, barley, oats, potatoes, sugar beets, timothy, and wheat. Apple orchards are common. Many of the highways are lined by trees, and almost every group of farm buildings is shaded and sheltered by Lombardy poplars. This tall poplar, a native of Europe, is a favorite because the trees grow rapidly and, if planted in rows close together, make excellent windbreaks. They are propagated by means of cuttings. While viewing this prosperous and beautiful rural country the traveler should bear in mind that only a few years ago, not further back than 1885, the entire Snake River plain was one great sagebrush desert, wholly barren of trees and populated mainly by jack rabbits, coyotes, and rattlesnakes.

Wapello in 1914 was a new settlement consisting of a store, a school, and a railroad siding. The trees about a mile to the west are on the bank of Snake River, the main stream of southern Idaho. The name of the river is said to be the translation of the name of a tribe of Indians, the Shoshones, who live along its banks. The river rises among the high peaks of the Rocky Mountains in Yellowstone National Park, flows southward, broadening into Jackson Lake, and then northward, and near Rigby, Idaho, is joined by Henrys Fork, locally known as the North Fork, which rises in Henrys Lake, near the Idaho-Montana State line. The portion of Snake River above Henrys Fork is locally known as the South Fork. These two streams receive numerous tributaries, much of whose water the year round is melted snow. Below the confluence Snake River flows in a general southwesterly course for 150 miles, to a point a short distance below the American Falls, where it turns nearly westward.

The small settlement of Firth, which was started about 1911, is on the Snake River flat or first bottom. A three-span steel highway bridge crosses the river near by. Half a mile north of Firth the river itself first comes into sight from the train. The bluff rising to the second bottom is just east of the track. Five miles east of Firth a second bluff rises about 50 feet to a third flat or bottom. This flat is composed of material brought down from the mountains by Blackfoot River and deposited on the plain at the mouth of its canyon.

Blackfoot River has had a hard fight for existence. When the earth's crust cracked and broke and quartzites and limestones were faulted up across the river's course, it kept its place by grinding down its bed. The upturned hard rocks made a mountain range through which the river cut a narrow valley. This valley was afterward flooded with rhyolitic lava and the river had to grind its bed down again. After it had regained its grade through the rhyolite that blocked its course a stream of molten basaltic lava flowed down the channel, and for a long time all water that came this way was turned to steam. When the hot lava became cold rock Blackfoot River began a third time the task of sawing its bed down to grade. It has now sunk a deep, narrow canyon in the black basalt so deep that the road up the river is on a bench 100 to 300 feet above the stream.

The mountains east of Firth and Monroe, rising 7,000 feet above the sea, or 2,500 feet above the plain, are mostly made of limestone of Carboniferous age or older. They contain also younger rocks, but all the beds are so tilted and broken up that their relations are difficult to determine. Some of the mountains are included in the areas of phosphate land withdrawn, for high-grade phosphate rock has been found here by members of the United States Geological Survey.

The belt of irrigated land on the west side of Snake River at Firth is very narrow, owing to the fact that the "lavas" are close to the river. By this term is meant the area in which black lava, crumpled into low ridges, makes a rough surface with very little soil. Many of the ridges are cracked open along their axes as a result of internal movement after the surface of the lava had cooled. These cracked folds are called pressure ridges. The soil on the "lavas" is too poor and thin to be cultivated, and is used only for pasturage. Farther downstream the "lavas" recede from the river bank, and irrigation projects¹ have made great tracts of desert available for settlement.

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¹Water is diverted from Snake River at the Minidoka dam, 80 miles below Blackfoot, and at the Milner dam, 35 miles farther west. Jackson Lake, in Wyoming, just south of Yellowstone Park, has been made into a great reservoir in which 380,000 acre-feet of water, or enough to cover 380,000 acres to a depth of 1 foot, is now stored by the United States Reclamation Service for use on the Minidoka project. During 1914 work was in progress of raising the dam at the outlet of the lake to such an extent as to make it possible to store 780,000 acre-feet. The expense of this new work is being borne by the North and South Side Twin Falls projects, and the additional water obtained will be used on these projects.

The Minidoka project includes 117,000 acres and during 1913 81,518 acres was actually watered. The principal crops raised here are alfalfa, grain, wheat, oats, barley, potatoes, sugar beets, miscellaneous hay crops, and fruit—chiefly apples. Stock raising and dairying are thriving industries.

At the Milner dam water is diverted for irrigating lands included in the North and South Side Twin Falls projects. The exact area to be irrigated has not been definitely determined but will be about 400,000 acres. During 1913 about 150,000 acres lying within the South Side tract was watered and in cultivation. The land is used for alfalfa, wheat, oats, pasture, apples, potatoes, and peas. Sheep and hog raising are profitable industries. The crops raised on the North Side tract are similar.

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Two miles north of Monroe siding and 1-1/2 miles east of the track there is a low sandy hill, on the top of which is the reservoir in which the water supply of Shelley, pumped from a deep well, is stored. This hill is basalt partly mantled with drifted sand. Northeast of it there is a series of moving sand dunes extending for about 8 miles in the direction of the prevailing winds.

Shelley is the trading point for several small settlements away from the railroad and is the center of an irrigation district which has been brought to a high grade of cultivation.¹ A hydroelectric plant on Snake River, 2 miles north of Shelley, develops about 8,000 horsepower for use in this part of the valley.

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¹The variety of products of this type of land is shown by the freight shipments made from Shelley from July 1, 1913, to June 30, 1914. According to the statement of P. J. Bennett, a notary public in Shelley, the shipments, in carloads, were: Wheat, 49; oats, 34; potatoes, 937; beets, 722; live stock, 104; mill stuff, 37; hay, 25; apples, 6; miscellaneous, 31; total, 1,945 carloads, or more than 74,000,000 pounds.

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West of Shelley the three buttes previously described are plainly visible far out on the Snake River lava plain. East Butte (Pl. XXX, B, p. 112) appears to have two sharp peaks between which there is a saddle-shaped depression. Big Butte has a less pronounced sag top, and Middle Butte shows a gentle south slope and steep north slope, which indicate that it is not a volcano. To the northeast, beyond the first low range of lava hills, is the crest of the Caribou Range. In very clear weather one can see more than 70 miles away a snowy peak coming into view over the crest of this range. This is Grand Teton, 13,747 feet high, the culminating peak of the range lying west of Jackson Hole and the largest of the three peaks which have been known as the Tetons or the Pilot Knobs since the members of the Astor expedition first saw them in 1811. (See p. 17.)

At Cotton, a railroad siding 3 miles south of Idaho Falls, named for the owner of an adjoining ranch, an electric-power house may be seen on the bank of Snake River. Just north of Bach, another siding 1-1/2 miles south of Idaho Falls, is a grove in Tautphaus Park. This is the local fair ground, where the annual War Bonnet round-up is held. Every September for five days Idaho Falls is thronged with visitors. They come to see cowboys and Indians with their race horses, bucking horses, and wild steers gathered here to amuse the crowd and to contest for prizes in feats of skill in riding and rope throwing. The War Bonnet round-up is to Idaho what Frontier Day at Cheyenne is to Wyoming and the round-up at Pendleton is to Oregon.

The city of Idaho Falls has a significant name and its site has had an interesting history. Snake River¹ here falls over the edge of a lava flow, and the incessant wear of the running water has cut the falls back into the lava sheet fully half a mile and they are now at the head of a narrow canyon, the walls of which are at one point barely 50 feet apart. Here a toll bridge was built in 1866, and the toll money collected from the freighters over the Utah-Montana trail started a store and the store started a town. The town was called Eagle Rock, because for many years an eagle had a nest on the large rock in the stream just above the bridge. The name was changed to Idaho Falls a few years ago. Snake River forms the west boundary of the city, and the falls, the eagle rock, and the site of the original bridge are only three blocks west of the railroad.

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¹The mean discharge of Snake River at Idaho Falls from 1890 to 1892, inclusive, was 10,300 cubic feet a second.

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Steel was laid on the main line north from Idaho Falls in 1879, and the railroad was completed to Silverbow, 6 miles from Butte, Mont., in 1881. The branch line to Yellowstone was completed in 1906. In 1914 a loop around the valley was being built from Idaho Falls northeastward to cross Snake River (South Fork) below Heise Hot Springs and thence go north to St. Anthony.

Idaho Falls owes its prosperity to the large quantities of farm products raised in its vicinity and is the most important shipping point between Ogden and Butte. Practically all the land in this part of the valley is in a high state of cultivation under irrigating ditches. The average yield of grain to the acre in the upper Snake River valley, on irrigated and dry land taken together, is estimated to be as follows: Wheat, 40 bushels; oats, 70 to 75 bushels; potatoes, 200 bushels; and beets 14 tons. These averages are far below what the successful rancher gets, for oats on irrigated land make from 50 to 120 bushels an acre and weigh from 40 to 44 pounds to the bushel. Two hundred bushels of potatoes is a light yield, 200 sacks or 400 bushels a good yield, and it is reported that as high as 700 bushels an acre have been raised in one 20-acre tract. In 1913 the district between Blackfoot and St. Anthony shipped 5,000 cars of potatoes, Idaho Falls alone being the shipping point for 2,500 cars. Potato bugs are as yet unknown in this region. Wheat on irrigated land yields from 40 to 60 bushels, weighing from 60 to 63 pounds to the bushel. It is reported that one tract of 720 acres averaged 38 bushels an acre in 1913, and as much as 70 to 75 bushels an acre has been produced in 10-acre tracts. It is said that almost no commercial fertilizer is shipped to this country. Crop rotation is practiced. When oat fields fail to yield 85 bushels an acre, some ranchers sow them with alfalfa or clover for a few years. Seed peas and beans for planting kitchen gardens from Maine to California are grown in the upper Snake River valley, and a seed-cleaning mill stands near the Idaho Falls station. Raw land with water right sold in 1914 for $40 to $60 an acre, and improved land brought $65 to $160 an acre, depending on the improvements, the lay of the land, and the location.

Red Duroc Jersey hogs are favorite money makers in this region, and sheep and cattle are ranged in the mountains in summer and pastured at the valley ranches in winter. The honeybee is respected and encouraged to greater industry. One man in this vicinity has 600 colonies of bees and keeps 4 tons of honey for their winter feed. Another bee keeper in the valley has 3,000 colonies. A factory at Idaho Falls extracts, stores, and ships hundreds of tons of alfalfa and sweet-clover honey every year.

A round stone tower (used as a tool house), which stands on the lawn at the north end of the Idaho Falls station shows the fitness of the local lavas, rhyolite and basalt, for use as building stone.

Soon after leaving the city¹ the train passes the first beet-sugar factory built in Idaho. It was erected in 1903 at a cost of a million dollars and has added much to the growth of Idaho Falls. Lincoln, a settlement of 300 people around the sugar factory, is reached by a branch line.

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¹Mileposts north of Idaho Falls give the distance from this junction.

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St. Leon is a siding at the crossing of Willow Creek. Far to the east, if the air is clear, two of the three Teton peaks are visible, and on the west, 12 miles from Idaho Falls, there is a low, broad, slightly sag-topped cinder cone, which holds a bowl-shaped depression about a quarter of a mile in diameter. Near this cone in 1914 there was a single tract of about 2,000 acres of dry-farm wheat.

The sagebrush plain just north of Ucon suggests what the whole valley once was, and the fertile fields already passed show what can be done by irrigation. Very little of the soil of the Snake River plain is derived from the basalt on which it lies. There is an abrupt change from the soil to the lava, and the exposed surface of the lava shows practically no trace of disintegration. The soil near the rivers, on their present or former flood plains, is largely river deposit, and that near the mountains is mountain waste, but the fine soil that covers the plains at a distance from the mountains is mainly wind-blown dust, which has accumulated gradually in the centuries since the basalt was poured out. The sources of the dust are the naked cliffs in the mountains, talus slopes, stream deposits on the margin of the plains, and volcanic ashes. The Market Lake Craters (see p. 137), truncated volcanic cones 10 miles northwest of the track, and other volcanoes of that type threw out large quantities of volcanic dust. A vigorous growth of sagebrush attests the good quality of the soil.

Near Ucon, as elsewhere in the valley, all trees except those along Snake River have been planted by the settlers. The main highway from Idaho Falls to Yellowstone Park parallels the railroad for several miles, but farther north it follows section lines, making the distance between towns by the highway somewhat greater than the railroad mileage.

North of Ucon the summit of the third and lowest of the three Teton peaks comes into view; farther north, at Ashton, they come into full view. The Teton Mountains were named from an Indian tribe. In "Astoria," Washington Irving's entertaining description of John Jacob Astor's expedition which crossed this country in 1811 on its way to establish a trading post at the mouth of the Columbia, there is the following reference to these mountains:

September 15 one of the guides pointed to three mountain peaks glistening with snow, which rose, he said, above a fork of Columbia River. These remarkable peaks are known to some travelers as the Tetons; as they had been guiding points for many days to Mr. Hunt, he gave them the name of the Pilot Knobs.

The Astor party came into Idaho near Victor, the present terminus of a branch of the Oregon Short Line at the west foot of the Tetons, and followed down the valley of Teton River, reaching Henrys (North) Fork of Snake River near the present site of St. Anthony, where there was then a "fort" established by Mr. Henry, of the Missouri Fur Co. At the fort they built canoes and started down Snake River. The next day they reached some falls about 30 feet high, took another day to portage around them, and then pursued their journey southward from the present site of Idaho Falls. They soon found the river unnavigable, had to abandon their canoes and strike across country, and endured terrible privations the following winter, the account of which is told in thrilling narrative by Irving.

A branch railroad running northwest from Ucon passes through Menan, 2 miles south of the Market Lake Craters.

Rigby is the largest town in the east end of Jefferson County and is the trading and shipping point for an agricultural district having a population of several thousand. It was organized in 1886 by the Mormon apostle John W. Taylor, from Utah, and William F. Rigby, of the local church authorities. A post office was established in 1888, and the railroad came in 1899. Within 15 or 20 miles above Rigby, on Snake River, are the headgates of a dozen or more canals in one stretch of the river—a canal every three-quarters of a mile. These canals, when full, carry every minute enough water to flood 8-1/2 acres to a depth of more than 1 foot. This great system of canals was built not by the Government or by promoters, but by the ranchers whose land they irrigate. The first canals were built between 1879 and 1884, when settlement began in this section. Potatoes are the leading crop near Rigby and a common yield is 300 bushels an acre. Under especially favorable conditions of soil treatment 700 bushels are said to have been taken from 1 acre. Wheat is reported to average about 45 bushels an acre, oats 65 bushels an acre, and beets 20 tons an acre.

Heise Hot Springs, 11 miles east of Rigby, is a resort on the north bank of Snake River (South Fork), at the foot of the wall formed by rhyolite tilted and overlain by horizontal younger lava flows. A log hotel that will accommodate about 150 guests and a bathhouse with two concrete pools have been built at hot springs which issue from the bank of the river. The springs have temperatures of 126° to 140° Fahrenheit. The water smells of sulphur and is strongly mineralized. Bathing in it is said to relieve rheumatism. Fishing is popular at this resort in summer and elk hunting in winter.

For a number of miles north of Rigby the railroad crosses a delta-like deposit built by Snake River. The stream brings great quantities of sediment down from the mountains, and here, on the Snake River plain, where the grade of the stream is decreased and its velocity is slackened, much of its load has been dropped. As a result, a low, broad fan has been built up, across which the river now flows in a number of channels. Henrys Fork joins Snake River at the base of the two craters seen a few miles to the west.

Between Rigby and Lorenzo the railroad crosses the "dry bed" of Snake River. This was formerly the main watercourse, but in 1894 the current shifted to the channel it now occupies, north of Lorenzo. At times there is water in the old channel, as part of its upper course is used as an irrigating canal.

The beet-loading platform at Lorenzo indicates one of the principal crops in this vicinity. Just after passing the station the train crosses the main channel of Snake River, which at this point is 500 feet wide.¹

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¹The discharge of Snake River at Heise Hot Springs, about 10 miles above this bridge, in 1910-1913, averaged 8,920 cubic feet a second. The maximum and minimum recorded discharges are 36,000 and 2,310 cubic feet a second.

The river passes through several canyons where dam sites could be found. The fall between Jackson Lake and Henrys Fork is about 2,000 feet. A large amount of potential power therefore exists along this stretch of Snake River.

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The Market Lake Craters, 4 miles west of Lorenzo, are two low buttes, broad of base, with gently sloping sides and broad tops, rising 500 to 600 feet above the surrounding plain. Each butte has an oval base measuring about 1 by 2 miles, and each has a well-defined crater in its summit about half a mile in diameter and 150 to 200 feet deep. The beds of ejected material slope away in all directions at sharp angles around the rims of the craters and flatten toward the base, where they become nearly horizontal. Within the crater rim the beds slope toward the center. Sand and gravel contained in the strata of which the craters are built indicate that these volcanoes were upheaved somewhat explosively through an old river or lake deposit. There is nothing to show that either cone poured out a lava stream. Material brought into the craters by rain wash and wind has given fairly level floors to the broad bowl-shaped depressions. The two cones are supposed to be of about the same age and are moderately recent. The name was derived from their proximity to Market Lake, a former shallow body of water so called because ducks congregated on it in such numbers that hunters went there regularly for a supply of meat.

A black volcanic tuff, an open-structured rock made of partly cemented fragments and dust produced by volcanic explosions, is used for building in the vicinity of Rigby and Rexburg. This rock is quarried on the bank of Snake River at the base of the Market Lake Craters. Houses are built also of the pink rhyolitic lava which occurs abundantly in the hills at the east edge of the Snake River plain.

After crossing Snake River the train goes through a grove of native cottonwoods along the channels of the river. This is the only natural grove on the railroad between Ogden and the Targhee National Forest, north of Ashton.

A mile or two east of Thornton a bluff rises abruptly 100 feet or more to a bench. The foot of this bluff is the boundary between the rhyolite that forms the low hills to the east and the basalt that makes the floor of the Snake River plain. The relative ages of the two rocks are indicated by the fact that the rhyolite is deeply weathered and in places its beds are disturbed from their original nearly horizontal attitude, while the basalt is unweathered and its horizontal beds abut against or overlap the older rhyolite.

Several miles to the west there is a low-lying light-colored band of sand dunes with a group of hills at its north end.

From Winder, a siding and beet-loading platform, a clear view may be had of the Market Lake Craters. Concrete tile for culverts is made here from sand and gravel dug beside the track. Near Rexburg the train crosses a large irrigating ditch, the water for which is taken from Teton River. Ricks Academy, a Mormon school, stands near the edge of the town. The numerous Mormon schools and churches in this region attest the fact that eastern Idaho was settled with the overflow population from Utah. In the late seventies and early eighties the fertile spots of northeastern Utah were already occupied and the stream of emigrants moved northward into Idaho.