32 GEOLOGICAL SURVEY OF THE TERrtlTORIES. 



been elevated tlirougli the more modern formations. The high group 

 ot mouiitaiii peaks to the southwest of Junction Station are composed 

 mostly of Carboniferous limestones and quartzites. The series of rocks 

 as exposed here may be arranged in asceuding order as follows: First. 

 A series of reddish, yellow and brown calcareous shales. Secondly. Lime- 

 stones, the ui)i^er portion of which is a coarse conglomerate, made up 

 mostly of water-worn masses of limestones, with abundant fossils, Spi- 

 rij'cr, Froductiis, Corals, Crinoid steins, with Aihyris suhtilota. Thirdly. 

 Capping the mountain is a quartzose sandstone light-gray or weathering to 

 a dark-brown, with a reddish tinge. In the valley of a little creek tbat 

 cuts the hills on the north side of the road near Junction Station, I en- 

 deavored to ascertain the character of the formations as far as they were 

 exposed. Commencing at the base, we find a yellow arenaceous clay, pass- 

 ing up into a yellow sandstone, rather friable, sometimes quite fine-grained ; 

 again a sort of pudding-stone or pebbly conglomerate. 50 to 100 feet 

 above is a curious conglomerate made up mostly of water- worn masses 

 of Carboniferous limestone, varying in size from the fraction of an inch 

 to several inches in diameter. The thickness of the entire group of rock 

 I estimate at from 1,500 to 2,000 feet. Still further to the northward 

 are rounded grassy hills composed of softer beds with a reddish tinge, 

 passing gradually' into brick-red beds, which may be Jurassic or Triassic. 

 lied Rock Valley is very beautiful to the eye. The stream is about 

 twenty yards wide, with a narrow valley, north of the junction, but 

 toward its source it expands out to a width of ten miles, forming a 

 splendid upland meadow. This valley extends up twenty-five miles, 

 with an average of ten miles in width. On the north side of this stream 

 there is a high and quite picturesque ridge, composed wholly of the red 

 beds, with perhaps some gray Jurassic rocks on the summit. The dip is 

 ])lainly northeast, and varies from 15° to 30^. Toward the source of Eed 

 ilock Creek, a high ridge on the south side of the valley reveals the rocks 

 well, inclining southeast 10^ to 15^. This ridge seems to have 

 been influenced by a distant range, which has raised the beds lower down 

 on the creek. The limestones and thick group of beds above^ extend 

 oH' in detached ridges, like steps, toward the river of Snake Basin. 

 One of the most singular features of this region is the immense 

 thickness of coarse conglomerate, apparently forming a portion of the 

 Carboniferous series. These conglomerates appear to be local, and occur 

 nowhere else, so far as my observations have extended. In the high peak 

 near Junction Station the beds are well shown from the oldest exposed 

 in this region. The Carboniferous rocks lie at the base, and gradually 

 pass up into the conglomerates, with no want of conformability. In this 

 mountain an immense thickness of rock seems to have been lifted up 

 vertically, so that at an elevation of 9,000 feet they are nearly horizontal, 

 while on one side the beds lapped down so as to be nearly vertical. On 

 the summits is a great thickness of quartzites. The conglomerates 

 seem to have been formed of pre-existing Carboniferous limestones 

 almost entirely. The cement is calcareous in some instances, itself a 

 limestone of fine texture, and the masses of limestone and other rocks 

 inclosed have been very much rolled in waters. How great an area this 

 conglomerate occupies I did not determine, but it is evidently not large, 

 probably not over fifty or one hundred square miles. Far to the east- 

 ward, seventy to eighty miles distant, the Tetons are distinctly visible. 

 For a hundred and fifty miles west of these mountains are many ranges of 

 hills, some of them rising to the dignity of lofty mountains, between 

 10,000 and 11,000 feet above the sea, with no rocks older than Ciirbonif- 

 erous exposed. For one hundred to one hundred and fifty miles along the 



