BMM0K8.] 



FACPRSIOX TO SHOSHONE FALLS. 3f3 



w hich flows somewhal to the south of west The. country now 

 assumes the desert aspect characteristic of the lava plains, treeless and 

 waterless, the rocks bare or covered in the hollows with the common 

 fleserl shrub, the sage-brush (Artemisia). No rivers flow into the Snake 

 rivet from the north, although many bold mountain streams have 

 flowed out upon the borders of the lava plains from the mountains 

 which form its northern boundary. These are known as Lost rivers; 

 and. while much of their water lias undoubtedly been dissipated by 

 evaporation, no inconsiderable portion must have found its way down- 

 wards through the cracks and rifts in the lava to the rocky bed over 

 Which it was originally spread out. This water, gathered into subter- 

 ranean streams of considerable volume, pours out along the walls of 

 the Snake river canyon to the southwest, below Shoshone falls, where 

 the corrasion of the stream has cut down below the base of the basalt 

 into the underlying andesite or dacite. 



From Shoshone station the stage route leads south over the same 

 monotonous barren plain, which has a scarcely perceptible inclination 

 toward the river. Long before the canyon in which it runs can be dis- 

 tinguished in the level monotony of the plain, the presence of the 

 stream is indicated by the thundering roar of waters as they fall. 

 Suddenly one comes upon the brink of the gorge. A steep descent of 

 400 feet (122 m.) leads down to the banks of the river above the Sho- 

 shone falls. 4 ' The travelers are ferried across the river to a com- 

 fortable little hotel near the brink of the falls, having a view down the 

 canyon below, which is 020 feet (190 m.) deep. These falls are more 

 broken and varied than Niagara; their height is greater, being 212 feet 

 (66 m.) instead of 166 feet (48 m.),but the volume of water is less, 

 though still very great, especially in the early summer, and the country 

 around has the desolate grandeur of the desert instead of the brilliant 

 verdure of the thickly-populated region in the vicinity of Niagara. 



The canyon presents a striking contrast to that of the Yellowstone 

 river both in coloring and form. The Yellowstone canyon is brilliant 

 and light-colored, with innumerable vertical pinnacles and spires; the 

 Snake Piver canyon is somber and black, with predominantly horizon- 

 tal lines marking the successive sheets of basalt, which are, however, 

 vertically columnar. The first is cut in a rhyolite plateau, the second 

 in a basalt plain. 



The basalt consists of three sheets, which form the upper 250 feet of 

 the canyon. The lower 260 feet, just below the falls, is massive ande- 

 site of an abnormal type, approaching dacite in chemical composition. 

 Its upper portion near the ferry is glassy and resembles certain modi- 

 fications of the rhyolite of the Yellowstone National Park. Where 

 the plateau of the Yellowstone Park descends into the plain of the val- 

 ley of the Palls river, a tributary of the Snake, the same geological 



