GEOLOGICAL SUEVEY OF THE TEREITOEIES. 17 



of rusty-brown slaty clays 200 feet thick. Then succeeds a remarkable 

 group of quartzite beds, with unusual indications of shallow water 

 deposition, inclining 75°. The river cuts directly through the ridge, 

 forming a caiion 100 feet wide, with walls 500 feet high. The lower 

 bed I have estimated at 2,000 feet in thickness, and it is mostly a close- 

 graiued compact quartzite, but sometimes it is an aggregate of small 

 white masses of quartz and water- worn pebbles. From underneath this 

 bed are a few 'outcroppings of micaceous gneiss and reddish feldspathic 

 granite, apparently inclining the same with the quartzites. 



There is another very interesting feature in this canon which connects 

 it more immediately with the great valley to the west of the range. 

 Toward the sources of Ogden Creek, and in the expansions of the 

 valley, are quite thick deposits of a kind of drift of sands and clays, with 

 the greatest abundance of loose, worn bowlders and pebbles. In the 

 caiion this drift material forms a massive, coarse conglomerate, and frag- 

 ments now are found atta(ihed to the sides of the canon in a horizontal posi- 

 tion. These conglomerates X)oint to the time when the great fresh-water 

 lake, at a comparatively modern period, filled the valley of Salt 

 Lake high upon the flanks of the mountains, even covering the highest 

 terrace. 



This subject will be discussed more fully in a subsequent portion 

 of this report. 



On the morning of June 11, we left our camp near Ogden City 

 and proceeded on our journey northward, cam]3ing the first night; 

 near the Hot Springs. This is a very interesting locality, and de- 

 served a more careful study than we were able to give it. There Is 

 here a group of warm springs, forming, in the aggregate, a stream 3 

 feet wide and 6 to 12 inches deep; the surface, for a space of 300 or 400 

 yards in extent, is covered with a deposit of oxide of iron, so that it 

 resembles a tan-yard in color. The temperature is 136°. They flow from 

 beneath a mountain called Hot Spring Mountain, which is about five 

 miles long and three wide, and is, I think, a remnant of the west part 

 of the anticlinal of which the great range forms the eastern part. On 

 either side of this fragment of a mountains the terraces are distinctly 

 defined. Tbe nucleus is composed of micaceous gneiss, with seams of 

 white quartz running through it in every direction, and resting upon it 

 with apparent conformity are the quartzites and limestones. Tiie eleva- 

 tion of tbe shore of the lake near the water- tank, not far from Hot Springs, 

 is 4,191.4, while the highest point of this broken mountain to the east 

 of it is 4,986.6, or about 800 feet above the lake. The water of the warm 

 springs is as clear as crystal, containing great quantities of iron, and 

 the supply is abundant, and as there are cold springs also in the vicin- 

 ity, there is no reason why this locality should not at some future period 

 become a noted place of resort for invalids. The medicinal qualities of 

 the water must be excellent, and the climate is unsurpassed. 



Between Willard City, and Brigbam City the terraces are well defined, 

 and the sides of the mountains, as the edges of the strata project 

 toward the lake, present a remarkably rugged appearance. The 

 limestones crop out here and there upon the quartzites without 

 any regular dip. I sought earnestly for some unmistakable proof 

 that this fragmentary mountain is a remnant of the west portion of the 

 anticlinal, and though I am convinced that it is so, yet the evidence was 

 not as clear as I could wish. Tbe terraces, as well as the sides of the 

 mountains, are covered so thickly with a kind of local drift or a modern 

 lake deposit that the underlying i"ocks are concealed. S"ear Box Elder 

 Canon are two kinds of terraces, the usual lake terraces, of. which, there 

 2 a s 



