GEOLOGICAL SUEVFA' OF THE TERRITORIES. 77 



tbe day the atmosphere appears nnnsnally clear and transparent,- and 

 every peak and canon stands ont in a relief so bold that one seems able 

 to look into the very recesses of these grand ranges. So close do they 

 appear to the beholder, and so distinctly are the details bronght out, 

 that they seem to lose a portion of that dignity which arises from their 

 grand loftiness. The mountains on the south side of the valley from 

 Spring CaQou to tlie cafion of the West Gallatin are not very rugged, 

 and are covered more or less with timber and a vast amount of super- 

 ficial material, concealing the rocks, except in the valleys of the streams. 

 The valleys or gorges of the streams that issue trom the mountains 

 disclose the strata of Carboniferous and Silurian limestones, and, thougli 

 the beds are thrown into remarkable confusion, yet the g'eueral inclina- 

 tion is evidently northeast. The great mass of the bowlders that are 

 brought down the caiions into the bottoms below is of igneous origin. 



In the morning the east ranges are usually covered with a, smoky 

 haze which makes them appear distant and indistinct, while the ranges 

 opposite the sun are brought out with a singular relief. In no country 

 are the varied phases of scenery better shown than in this. For the 

 artist this country must open up a new world. 



We will now ascend the Gallatin CaGon to the source of the river. 

 This caiion had never been explored by any scientific party previously, 

 and even the settlers in the open valley below knew nothing about it. 

 A few hardy miners had ascended it in search of precious minerals. 

 The Gallatin River seems as it were to be crowded in between the two 

 great rivers, the Yellowstone and the Madison, and it has therefore 

 cut a continuous gorge through the rocks for more than seventy miles, 

 with walls ou either side rising from 1,000 to 2,000 feet. As a geolog- 

 ical section it has hardly a parallel in the West. On this account, as 

 well as from the noveltj' of the region, I wish to describe the caiiou in 

 detail. 



Just ou the west side of the Gallatin, about half a mile below the 

 caiion, is a ridge of Pliocene sands and sandstones, inclining at a slight 

 angle from a thin series of arenaceous limestones. Then comes a ridge 

 or two of the older limestones, probably Silurian, inclining 10*^. Then 

 underneath, and farther up the caiion, the reddish feldspathic quartz- 

 ites and other rocks apparently conforming at this locality. The river 

 at the mouth of the canon is 100 to 150 feet wide, and rolls swiftly over 

 its rocky bed, with an average depth of 12 to 18 inches. There are 

 ■well-marked terraces along the river, though not peculiar, like those on 

 the Madison. At the lower portion of the caiion the gneissic rocks are 

 well exposed, the hills on either side rising to a height of 000 to. 1,000 

 feet, with the strata nearly vertical or inclining northwest. At first 

 view the limestones seem to conform with the granitic strata, but the 

 former dip northeast, the latter northwest, 50° to 80°. The peculiar 

 banded appearance of the gneiss is shown in a marked manner. 



About three miles up the cafion, near the entrance of Spanish Creek, 

 the Gallatin flows between uplifted ridges of limestone. The river 

 flows nearly north, while the inclination of the limestone-beds is about 

 northeast, and the channel is cut partly across the ridges and partly 

 in the intervals between. So that on the east side the limestones pre- 

 sent a remarkable wall of the outcropping edges of the strata, 1,000 to 

 1,500 feet in height. In looking directly at "the wall the strata seem 

 nearly horizontal, but a side view shows the dip to be 15° to 25°. On 

 the west side of the Gallatin the strata incline like a steep roof and the 

 ridges of arenaceous limestone rise to a height of 1,800 to 2,500 feet, 

 and are undoubtedly of Silurian age. Underneath the arenaceous 



