GEOLOGICAL SURVEY OF THE TEREITORIES. 137 



northeasterly course, pass up the valley of Pelican Creek, and cross the 

 mountains to the east branch of the Yellowstone. We have endeavored 

 to explore the great basin with all the care that our time and facilities 

 would permit. Much has been left undone, but we feel certain that we 

 have obtained information enough to convince our readers that the region 

 we have examined is invested with profound interest. We have explored, 

 with much care and detail, one of the most beautiful lakes in the known 

 world. Our soundings, which are expressed on the chart in fathoms, 

 show that its greatest depth is 300 feet. According to a careful series 

 of soundings of Great Salt Lake, Utah, by Mr. Dieffendorf, for the pur- 

 pose of finding the deepest channels for a steamer, the average depth 

 is only about 12 feet, while the greatest depth was found to be only 60 

 feet, and that was between Antelope Island and Stansbury Island. 



We traveled up the valley of Pelican Creek about eighteen miles. Hot 

 springs were scattered along the bottom, some of them of considerable 

 size and beauty. There were many dead and dying ones, some of 

 which indicated great age j the immediate bottom is incrusted with 

 the silica. The average width of the valley is about two miles, and at 

 this season of the year (August 23) the grass and other vegetation is 

 very fresh and abundant. If it were not for the elevation and climate, 

 this valley would soon be filled with enterprising, thriving ranchmen 

 and farmers. The valley itself is underlaid with the modern lake 

 deposits, which extend up almost to the divide. It is plain, from a sys- 

 tem of terraces more or less distinct, that the lake once extended high 

 up the vaUey, and that the fertility of the soil and the present 

 exuberance of vegetation are due to this fact. The broken range of 

 hills and mountains that inclose it on either side are covered with 

 forests of pine, and the rocks are entirely of volcanic origin — the 

 trachytes and conglomerate. Ten miles up the creek is a pretty little 

 cascade, where the waters pour over a descent of 15 feet, which is formed 

 of stratified sand and clay. Above the cascade there is a wall 60 feet 

 high, composed of Pliocene deposits. From the divide the view is far 

 extended and very fine. The Grand Caiion of the -Yellowstone, with its 

 group of hot springs, with the deep side-caQons that lead into it, and the 

 dense forests of pines, and the north rim of the basin, with the bald, 

 black summits of the volcanic peaks projecting above the tree vegetation, 

 all are presented to the eye at a single glance. 



We camped at night on the summit of the divide, between the valleys 

 of the East Fork and the main Yellowstone, by the side of a little lake 

 10,000 feet above the sea. The wonderful group of peaks which extend 

 along the source of the Yellowstone, and the branches of the Big Horn, 

 from the lake itself to the lower caiion, which constitute on the map, the 

 Heart and Snow Eanges, were in full view, with all their rugged grand- 

 eur. The basaltic cones and broken rims of huge craters were clearly 

 visible, while the equally lofty but more rounded, dome-like, conglomer- 

 ate peaks could be easily detected by their style of weathering. Deep, 

 aln^pst vertical gorges, led down into the valley of the East Fork on the 

 east side of us, and on the west into the main Yellowstone. Here and 

 there a white patch on the mountain-side or in a valley, looking like a 

 bank of snow, showed the former existence of a group of springs. 



We descended to the valley of the East Fork, and camped the night 

 of August 24 at the junction of the two main branches. Here we spent 

 one day exploring the east branch of the East Fork, which has its sources 

 high up among the most rugged and almost inaccessible portions of the 

 basaltic range. There are several wonderfully jagged peaks about the 

 sources of this branch, which rise up 10,000 to 11,000 feet above the sea. 



