UIl1 LIVINGSTON TO BOZEMAN. 365 



the railroad with fuel. The coal-bearing rocks are seen at- Mountain- 

 side, where the coals are also rained. West of here the road enters a 

 narrow gorge known as Rocky canyon, cut across a sharply folded 

 anticline pitching steeply to the north. The various formations of the 

 Cretaceous are seen passing up the hillside to the north and, together 

 with the Jurassic, curving around the massive limestones of the Car- 

 honit'erous. The latter rocks form the picturesque pinnacles and 

 towers of the central portion of the canyon. A little beyond, the Meso- 

 zoic strata are again seen, their sandstone beds curving about the 

 Carboniferous in sharp flexures. The ridge cut through by Rocky 

 canyon connects the Gallatin range to the south with the uplift of the 

 Bridger mountains to the north, and is really a low part of the Front 

 range of the Rocky Mountains, which is here broken down into a num- 

 ber of low uplifts arranged en echelon. The valleys are usually eroded 

 in the soft Cretaceous shales; the ridges show the resistant limestones 

 of the Carboniferous. 



Leaving Rocky canyon the road enters the broad intermountain 

 basin known as the Gallatin valley. Immediately north of the railroad 

 the bluffs of the East Gallatin river show fine exposures of Neocene 

 lake beds, the deposits here being conglomerates and coarse sand- 

 stones dipping at an angle of 3° to the northward. Fort Ellis, an 

 abandoned military post, is built upon these lake beds that form the 

 gently sloping table land southward, beyond which the peak of Mount 

 Ellis, formed of Carboniferous limestones, is seeu. 



[By Dr. A. C. Peale.] 



Between Bozeman and Central Park the road passes over the alluvial 

 valley of the Gallatin river. On the east side of this valley is the 

 Bridger range, in which the nearest foothills are composed of gneisses. 

 The portion of the Bridger range in sight from the railroad is a mono- 

 cline, mainly of Paleozoic rocks, Carboniferous limestones forming the 

 crest line, with Archcan gneisses on the west. At the south end of 

 the range the beds are overturned, the Cambrian, Devonian, and Car 

 boniferous beds inclining to the westward, with the older beds on top 

 dipping under the gneisses. 



Bridger peak is the prominent point at tins end of the range, while 

 farther north Ross peak, although not the highest, is the most rugged 

 prominent mountain seen from the railroad. South of the valley the 

 Gallatin mountains arc seen. They arc composed mainly of gneisses 

 and eruptive rocks. The most prominent peak, almost due south of 

 Bozeman, is Mount Blackmore. which is composed of andesite, while 

 farther to the west is the gneissie Gallatin peak. 



The Gallatin valley is one of the old lake basins, of which a large 



