Table showing the rise or fall in each mile of the line from Provo City to a point on Weber river, together with the corresponding fall of water in Timpanagos and Weber rivers.

Table showing the distance, difference in elevation, and the average grade per mile between some of the principal points on the preceding line.

APPENDIX No 2.

REPORT OF PROFESSOR JAMES T. HODGE, GEOLOGIST.

To the President and Board of Directors of the Union Pacific Railroad Company:

GENTLEMEN: In accordance with your instructions of October 15, 1863, I proceeded forthwith to the Rocky mountains for the purpose of investigating the capabilities of the region near the surveys for the Union Pacific railroad for making iron and producing mineral fuel.

By the overland stage line I reached the base of the Black Hills at Laporte on the 1st of November, to find the country covered with snow, rendering geological explorations altogether impracticable. Here I was detained a week, waiting for the surveying party I was to join, which was fitting out at Denver. On the eighth I had crossed the Black Hills, and in Laramie plains I first had an opportunity of investigating the mineral character of the country. In the prairie hills, three miles south 30° east by compass from the stage station called Big Laramie, (from the name of the river on the banks of which it stands,) I discovered a lean iron ore intermixed with veins of calc-spar, outcropping in flat bands almost black in color and in considerable quantity. Similar ore is again met with, covering the surface of the prairie on a direct line toward the stage station. It is a hematite at the surface, probably from atmospheric oxidation of a carbonate of the character of the clay iron-stone, such as is found in the coal measures. The geological formations in the vicinity are shales of olive, bluish, and brown colors, associated with slaty calcareous strata which contain sharks' teeth and other fossils that refer the group to the cretaceous period. Plates of selenite are abundant, scattered on the surface of the shales. Over the plains nearer the mountains to the east are occasionally met outcroppings of a reddish sandstone and a very close-grained compact limestone of light shades, flesh, straw, pink, blue, red, and some nearly white. This limestone would answer well for a flux in smelting iron ores. Coal is reported to be found near the forks of the Laramie in these plains, and is probably of similar character to the same mineral worked near Denver, (to be afterwards noticed,) which also is associated with iron ores and limestones. Though the iron ores I discovered appear too lean to be valuable, they afford a clew as to the geological relations of the ores of this region and the localities where they are most likely to be met with.

Approaching the Cheyenne Pass from the west, small rolled pieces of hematite are found, both in the wagon road and also on the side of a prairie hill a quarter of a mile north from it, which hill is capped by ragged ledges of red limestone in horizontal strata. The pieces of ore are smooth and hard and the quality is excellent; but there is no certainty of quantity sufficient for working. Further explorations, however, may lead to more important discoveries. Should such be made, iron works might be established near the mountains on one of the branches of Laramie river. Several tributaries to it of clear water, never fail. ing, run through the valley; seldom, however, with sufficient fall to afford water power. The limestones may be depended upon for flux, and fuel will be afforded either by the beds of mineral coal or by the pines of the mountains. The region, however, is generally deficient in good timber; none is seen on the prairies, and the growth upon the mountains is scattered and for the most part thin. It consists almost exclusively of pines, balsam fir, and quaking aspen. Of these the first will make suitable charcoal for smelting iron ores. Until recently such fuel alone supplied the blast furnaces on the shores of the Chesapeake, at Baltimore, and its vicinity. In the mountains further south, I afterward found spruce trees accompanying the pines.

The Medicine Bow mountains, on the west side of Laramie plains, appear to contain a heavier forest growth than the Black Hills, and should iron ore be found on that side of the plains it might prove a better region for the manufacture of iron than the eastern side. I proceeded as far west as Fort Halleck, on a branch of the Medicine Bow creek, and at the northeast base of Medicine Bow mountains, and sought to ascertain the locality of iron ore on this creek reported by Mr. Engelmann, who accompanied the expedition. Mr. Duval, who is still in government employment at Fort Halleck, was entirely ignorant of any such discovery. I learned, however, of the occurrence of coal beds, said to be of large size, in the prairie hills six miles northeast from Fort Halleck, and made several ineffectual attempts to find them. The east side of the hill, where they were discovered, I found covered deep with snow, and though I remained eleven days at Fort Halleck in hope of a favorable time for exploration, it was for nearly the whole period almost impracticable for one to cross the prairies and dangerous to leave the stage road. The wind every day blew with extraordinary fury, sweeping the snow forward and piling it in deep drifts in the cañons and gulches, and on the lee or east side of the hills. For days together a man could with difficulty stand up against it, and the driving snow often prevented his seeing one hundred yards in any direction. During this time the themometer ranged from zero to 10° below. It was the first day of December when I reluctantly left this portion of the Rocky mountains, in despair of making in it any useful geological observations at so advanced and inclement a season.

Before going to Fort Halleck, I accompanied the surveying party of Mr. B. B. Brayton through the Black Hills, on the Cheyenne Pass, leading from Lodge Pole creek to Salt lake; and it is for the sake of completing my account of the plains west of the Black Hills, before proceeding to that of the mountain district and the plains to the east of it, that I have introduced above my remarks upon the country about Fort Halleck.

At the Cheyenne Pass the Black Hill range, extending due north and south, presents a very uniform slope on its western side, but little interrupted by cañons, such as are of frequent occurrence in other portions of the Rocky mountains. This slope nearly to the summit is that of the limestone strata, which uplifted from their horizontal positions in the plains, here form the outermost layers of the range. In a gorge near the base of the mountain they are exposed to the thickness of full twenty feet, which is probably but a small portion of the real thickness of the formation. The rock is in broad, flat blocks, admirably suited for building-stones, and much of it, though never crystalline, appeared as if it might make a substantial marble of fair quality, but not of bright colors. I could discover no fossils in it. Beneath this rock, exposed in precipitous ledges along the gorges, and curving up from under it at the summit, is a red silicious sandstone resembling the Devonian red sandstone of the Alleghanies. It covers the surface of the hills lying north of the pass, spreading out over broad areas in nearly horizontal strata. These towards the east abut in bold cliffs, and next beyond them in this direction appear the granitic and porphyritic rocks which make up the central portion of the range. The only distinct fossils I could find in the sandstone were small encrenites. Neither this formation nor the limestone is likely to afford any useful minerals, though the latter may possibly prove a repository in occasional localities of hematite. Professor James Hall, of Albany, to whom I have submitted specimens of both the limestone and sandstone, refers the group to the carboniferous formation of the age of the true coal measures. The rocks which compose the mass of the Black Hills are red granites, red sienites, and red porphyritic sienites. They form not only the high ragged peaks and groups of rough hills that lie to the north and south of the pass, but the smoother surface and prairie-like hills of the pass itself are also underlaid by the same formation. A peculiar feature it everywhere exhibits is a decided tendency to disintegrate and crumble into

coarse, angular fragments. The surface is very generally covered with these, which make a poor soil enough, but the very best of roads. The wagon road through the pass, though unimproved by any labor upon it, is for the most part unsurpassed in smoothness and durability by any macadamized road. This tendency to disintegrate is also the cause of the numerous peaks and monumentshaped masses of all sizes standing on the steep mountain slopes and summits, and also scattered over the smoother and level portions of the mountains.

Some of these appear, like the boulders of northern latitudes, perched upon ledges from which they could be easily tipped off; others resemble icy masses along a frozen coast as they melt away on the approach of spring. In some instances, when the disintegration has gone on most rapidly at the base of towerlike masses, huge blocks have parted from the main body to which they belonged and have fallen down, exposing a fractured and nearly smooth face, sometimes of several hundred square feet area.

In general, the outline produced by the disintegration is rounded like that of rolled boulders. I could find in these formations no metallic veins, nor any features that would lead me to look for iron ores in the central part of the range. No mica nor talcose slates accompany the granites, and the only variation in the rocks is as they become more or less sienitic or porphyritic in their composition. Numerous quartz veins, however, are seen toward the eastern side of the pass crossing the road in a northerly and southerly direction, and projecting above the surface, which in their vicinity is covered with loose pieces of this mineral. These veins resemble the gold-bearing quartz veins of the southern States, but are unlike those of the Colorado mining district.

The granites also of that part of the Rocky Mountain range are very different from those of the Black Hills, being of light colors and gneissoid in struct

ure.

On passing out from the central range toward the plains on the east side, one every where meets facing the mountains a range of high, precipitous cliffs of red sandstone, the lower layers often conglomerate. These rocks present a thickness of full 500 feet, and as the lowest strata are not exposed, the formation may be much thicker than this.

It is evidently a repetition of the same sandstone group that caps the summit on the west side, and passes under the limestone that forms the western slope. This rock, too, lies in the same relative position to the sandstone on the east side, capping the cliffs in some instances, and also forming a parallel outer range of hills, the strata still dipping cast. All along the east side of the Black Hills, as far as I observed them, and further south where these hills are lost in the main Rocky Mountain range, this group of marginal cliffs is traced, and everywhere they present a striking feature in the topography, all the more marked by the bright red color of the sandstone.

Their forms at the Cheyenne Pass, and again at Boulder creek, Colorado, are represented in the accompanying sections and sketch, and their range is designated in the ground plan or map. The hills appear to have once formed a continuous unbroken line, the western summit presenting a bold escarpment, the base of which is covered by the debris fallen from above.

This constitutes the gentler slope seen in the section at the western foot of the hills. The eastern slope is that of the strata, and the surface on this side is frequently in chief part that of the rock itself, scantily overgrown with sage bushes, cactus, and grass that have taken root in the crevices. Behind the first range, with an intervening valley, sometimes nearly a mile wide, but much less further south where the dip of the strata is very steep, is a second range of precisely similar form, and near the Cherokee Pass, where the stage road crosses the mountains, I have observed a succession of four or five such ranges, the outermost one dying away in reduced dimensions in the prairie to the east. Their covering of snow prevented my studying the structure.

At the entrance to the mountains at Clear creek, Colorado, there is seen extending several miles north and south, outside of this range of hills, another group of basaltic formation.

The bills composing it are all remarkable for their peculiar tabular form, being perfectly flat on the summit, which is bounded on all sides by vertical walls, apparently a hundred feet high, of rudely columnar green-stone or hornblende rock. The summits are sometimes several hundred acres in area, and at others (as on one of most striking appearance just east of Golden Gate City) the extent does not seem to be more than three or four acres. In this, however, one may be deceived by the great height of the hill, which is probably full seven hundred feet above its base. These are the only hills of this formation I saw in the Rocky mountains. Their position is represented in the map, and their form among the sections accompanying it. The soil near their base is quite fertile, and is often cultivated for some distance up their very steep slopes.

This group, as also the more extended range of sandstone hills behind them, traced north and south, are seen to be interrupted at intervals of half a mile to a mile and a half by gaps, all of which are worn down to about the same level, which may be 300 to 500 feet below the summits. The mountain streams find their outlet through these gaps, and all the roads into the mountains pass up by the same openings.

The rounding away of the ends of the hills in the gaps toward the east, the direction of the dip, keeps exposed the strata, which in the face of the escarpment further west occupy a much higher position, and to an observer facing the escarpment the impression is conveyed that in each hill the strata at its northern end dip north and at the southern end dip south. In the middle of the face they appear to be horizontal, the basset edges only being in view.

The peculiar form of these hills is obviously due to powerful denudation directed from the central range eastward. On the shorter western slope of the Black Hills the effects of the same action in the opposite direction are less strikingly exhibited in the abutment of the same sandstone formation, which, as already noticed, is seen on that side near the summit of the range. Other evidences of extensive movements over the surface from the main Rocky mountain ranges eastward, will be presented in describing the formations examined further south.

The lower members of the limestone formation at the east entrance of the Cheyenne Pass are remarkably intermixed with various forms of silex, as flint, jasper, carnelian, and chalcedony, which sometimes present a rude agate structure. The flints are of many different colors; the jasper is in fine blocks of clear red. The sides of some of the hills are covered in places with fragments of these minerals, the flints aud limestone often attached together.

The operations of the party I accompanied being limited to the pass, I had no opportunity of extending my observations into the plains on the east side of the Black Hills. I had already become satisfied that it is in the plains, and not in the mountains, that the minerals I was in quest of are to be found, and after abandoning further explorations west of the mountains I proceeded to the region south of Laporte to investigate the character of the beds of coal and iron ore there opened and worked. The range of the formations, I had learned, would carry these beds northward near the Black Hills, and a knowledge of their properties, which could be obtained in a comparatively settled country, though still covered with snow, would be useful in directing further explorations in the wild districts about the Cheyenne Pass to one provided with the necessary facilities for conducting them in a more propitious season.

It was after leaving the pass that I learned from Mr. Duvall, at Fort Halleck, of the occurrence of iron ore in large quantity on the branches of the Chugwater, about twenty miles north from Camp Wallach, which is an old deserted camp at the east entrance of the Cheyenne Pass. His description of the ore as heavy