GEOLOGICAL SURVEY OF THE TEREITORIES. 



119 



which there are Pliocene sandstones. The columnar form is beautifully 

 shown iu many places throughout the valley. 



From Camp No. 3 I ascended the foot-hills which lie to the west, 

 bordering- the Yellowstone Valley. These hills rise about 3,000 feet above 

 the level of the river. Proceeding three miles from the river we reached 

 the base of the hills and found the lower ones composed almost entirely 

 of breccia, while farther back we find laminated trachytes, which are in- 

 clined at an angle of about 40°, as though the lava had been poured 

 forth in successive layers and, after cooling, had been tipped up by sub- 

 sequent volcanic action. It is probable that under this volcanic mass 

 we would find all the sedimeutary rocks, from the Cretaceous to the 

 Carboniferous or even lower. A few miles from the river, where the 

 small streams have cut deeply into the hills, we find rocks containing 

 Cretaceous fossils. Farther up, however, the volcanic rocks conceal all 

 the underlying formations. 



Our next camp, No. 4, was some eight or ten miles farther up the 

 valley, on a basaltic plateau near Bottler's ranch. The general eleva- 

 tion of this plateau above the river is between 100 and 200 feet. Near 

 Bottler's there are several good exhibitions of basaltic columns, and on 

 the opposite side of the river the underlying marls and white sand- 

 stones. A few miles west of Bottler's we find ourselves in the midst of 

 volcanic rocks of all kinds and colors, basalts predominating. The pre- 

 vailing color of these rocks is a brick-red and dull purple. Scattered 

 over the hills, as well as throughout the entire valley of the Yellow- 

 stone, we find chips of black obsidian, chalcedony, agate, and jasper. 

 I got some very 



good specimens of Fig. 29. 



red jasper associ- 

 ated with blue chal- 

 cedony, and also 

 specimens of oliv- 

 ine from the basalt. 



We left Bottler's 

 on the 24th, and 

 started up the val- 

 ley, camping in the 

 afternoon (Camp 

 No. 0) on CaQoii 

 Creek, eleven miles 

 above Bottler's. 

 Canon Creek joins 

 the YellowvStone 

 just after the latter 

 has emerged from 

 the second canon! 

 (Fig. 29.) The rocks 

 of the second canon 

 are all gneissic, and 

 as I described them 

 in the report for 

 1871, I will pass 

 them here. B e - 

 tween Bottler's and 

 the second canon 

 the trail leads us along the western side of the Yellowstone, being part 

 of the way at a considerable height above the river on blufts of volcanic 



SECOND CANON OK YELLOWS! ONE RIVER. 



