32 GEOLOGICAL SURVEY OF THE TERRITORIES. 



where almost vertical, and difficult of ascent, so that we were obliged to 

 follow up the rocky bed of a stream for a long distance. Hugh masses of 

 gneissic granite blocked our way at every step. In some of the caiions a 

 few bowlders of igneous origin were observed. The study of the different 

 kinds of rocks along (he course of any of these mountain-streams usuall^^ 

 gives one a pretty clear idea of the structure of the mountain in which they 

 have their origin. The fir-st ridge, which is about 3,000 feet above the riv- 

 er-bottom, is composed mostly of the meta^morphic quartzites. The second 

 ridge, which is about 500 feet higher, is composed largely of mica- 

 schists and granitoid gneiss. The limit of the vegetation is about 9,000 

 feet, where the small scraggy spruces lie prostrate, and are not more than 

 four feet in length. Above these no more tree- vegetation is seen. From 

 the summit of this peak, a broad area is compassed in the field of vision. 

 Far east and southeast, along the head-waters of the Stillwater, Big 

 Rosebnd, and Rock Creek, the gneissic rocks extend, with their sharp 

 ridgelike peaks standing up like pinnacles among the perpetual snows. 

 For fifty miles in every direction there is a chaos of mountain-peaks, 

 varying in form according to the rock-materials of which they are com- 

 posed. For grand rugged scenery I know of no portion of the West 

 that surpasses this range. The little streams have cut innumerable 

 gorges deep down through the very heart of the mountains, 2,©00 to 

 0,000 feet in depth, and the exceedingly close testure of the granites 

 and quartzites, of which the rocks are mostly composed, has prevented 

 the atmospheric forces from wearing off the angularities, so that they 

 appear as sharp and angular as if but recently brought to the surface. The 

 examples of ribbed or banded gneiss are quite remarkable for their perfec- 

 tion and regularity. The junction of the unchanged beds with the 

 metamorphic is remarkablj' well shown in the gorges on the north side 

 of the range. The general inclination of the limestone is about 30° to 

 50^ northwest. From this high point the ridge of limestone, with 1,200 

 to 1,500 feet of outcropping strata, may be n)0st clearly seen for a dis- 

 tance of twenty or thirty miles east and west, forming a remarkable 

 natural section. Extending far to the eastward and opening out into 

 the plains, are the gradually descending ridges of the Jurassic, Creta- 

 ceous, and Tertiary beds, presenting an irregular rugged surface depend- 

 ing upon the nature of the rock-materials of which they are composed. 

 The Yellowstone River really emerges into the plains below the junction 

 of Shields's River, and thence to the junction of the Yellowstone with the 

 Missouri the Cretaceous and Tertiary formations prevail. On either side 

 of the Yellowstone, at a distance, may be seen isolated small ranges of 

 mountains until we pass below the motith of Tongue River. 



II? is most interesting as well as instructive to explore with care 

 among the deep gorges which the watery agents have worn down through 

 these lofty mountain-ranges. The amount of debris or broken rocks 

 which one encounters excites surprise. Water and frost are ever at 

 work, and have been busy for ages in breaking down the sides of the 

 gorge and extending it farther back in the range. We discover here the 

 sources of the myriads of perpetual streams, which we find in the low- 

 lands, and which we see meandering through the plains like the veins in 

 the human body. Each one of these little streams, toward its source, 

 branches out into numbers of small tributaries like the capillary vessels, 

 and each one of these little capillary streams has eaten out its deep 

 gorge or caiiou, which adds to the rnggedness of the mountain-scenery. 

 There is in this Yellowstone Range an unlimited field for the artist ; 

 photographic views of the most startling kind could be obtained with- 

 out number. I am convinced that this range of mountains, and the 



