GEOLOGICAL SURVEY OF THE TERRITORIES. 37 



to the foot-hills; here the granites prevail. At first they have a fissile 

 structure to some extent, but soon become massive, like the granites of 

 Sweetwater Valley, except that the feldspar is white. The mass of the 

 Wind Eiver Mountains is gray granite, with here and there some red 

 feldspathic seams ; but as I found it in I860, when crossing the range 

 near the source of Wind Eiver, to the head of Lewis' Fork of the 

 Columbia, the central mass is mostly gray granite and wonderfully uni- 

 form in texture. Small masses of black gneiss are distributed through 

 the, granite. After entering the foot-hills we moved up the valley of 

 one of the various branches of the Sweetwater, through most rugged 

 scenery, among thick pines and over vast quantities of broken rocks or 

 debris. At last we reached a high ridge which forms the divide between 

 the waters that flow into the Sweetwater and those of the Sandy, and 

 near this ridge, at an elevation of over 10,000 feet above the sea, we had 

 a complete and near view of the Wind River range. Far above us rose 

 the snow-capped ridges of the axis of the range, with Fremont's and Snow 

 Peaks full in view. Fremont has given in his report the elevation of 

 Snow Peak, which is probably the highest of the range, as 13,570 feet. 

 One of the peculiar features of these mountains is the dense growth of a 

 kind of " nut-pine," which furnishes food for innumerable birds and 

 squirrels, and supplies the Indians with their favorite food. 



Washakie's band of Shoshones had been up in the mountains only a 

 few days before, and hundreds of the trees had been cut down for the 

 nuts. I should judge that the limits of arborescent vegetation is about 

 11,000 feet. On the south side of the range there is not much perpetual 

 snow, only here and there a patch ; but on the north side snow-banks 

 are extensive. 



From this high ridge we had a most remarkable as well as instruct- 

 ive view of the southwest side of the range. Far out in the plains the 

 long parallel ridges of the white tertiary marls could be seen, then 

 step by step the ridges of granite rising to the summit. The outline of 

 these granite ridges revealed most clearly the anticlinal character of the 

 range, their sharp summits pointing toward the snowy crest above 

 them. On the east side of the anticlinal the outcropping edges of a 

 high ridge of carboniferous limestone extend down toward the Sweet- 

 water near St. Mary's Station. The Silurian and carboniferous rocks 

 form a conspicuous wall on the east side ; on the west side, far up to the 

 head-waters of the Sandy, they seem to be concealed by modern tertiary 

 deposits. Not only the sides of the lower ridges, but the top and sides 

 of the central mass are covered so thickly and continuously with frag- 

 ments of granite that this becomes one of the most conspicuous features. 

 Both Snow and Fremont's Peak are one mass of debris. During the day 

 Mr. Jackson, with the assistance of the fine artistic taste of Mr. Gifford, 

 secured some most beautiful photographic views, which will prove of 

 great value to the artist as well as the geologist. We made our camp 

 at night near the foot of Fremont's Peak, by the side of a spring of the 

 purest crystal water, surrounded with a thick growth of fresh green 

 grass, that gave a manifest delight to our animals. We were on the Pa- 

 cific slope, and as the waters of the little spring passed by us, within a 

 few feet of our camp-fire, in the stillness of the night, we imagined we 

 could hear in its rippling music the faint echo of that of the great 

 ocean to which it was hastening. Among the numerous plants which 

 grew here, many of them with handsome flowers, I was attracted by the 

 great abundance of a species of trifolium, with a white blossom, about 

 the size of our domestic red clover of the States. There was also a 

 large species of allium which I have not observed before in the West. 



