76 GEOLOGICAL SURVEY OF THE TERRITORIES. 



along any line or axis of elevation, but each one, like a group of hot 

 springs, seems to have been a volcanic vent which built up its own cone. 

 The igneous rocks have been poured out over the metamorphic, plainly 

 at different periods. The general mineral character of the igneous ma- 

 terial is about the same, but the colors and textures are very variable ; 

 some of them are coarse, decomposing easily ; others rough, angular, 

 vesicular,, or compact ; some rod, purple, brown, black, &c. The study 

 ofthe immense masses of basaltic conglomerate which cover the country 

 everywhere, especially in the upper basin, affords the best opportuni- 

 ties of ascertaining the different varieties of the igneous rocks in the 

 country, for fragments of all kinds seem to have been included in the 

 volcanic paste. 



After leaving Gardiner's Eiver we ascended the broad slope of the 

 dividing ridge between that river and the little branches that flow into 

 the Yellowstone. Below and above the entrance of the East Fork, im- 

 mense bowlders of massive granite, considerably rounded, are a marked 

 feature. One of them, partially rounded by water, is 25 feet thick and 

 50 feet long, with a fracture directly through the middle. It is a mas- 

 sive red feldspathic granite. The ridge of Carboniferous limestone, which 

 is exposed on the west margin of the third caiion, extends up in frag- 

 ments for six or eight miles. It is very brittle and cherty. The high 

 vfuvj ridge, which is about 9,000 feet above the sea, is composed of beds 

 of steel-gray and brown sandstone, clays, and a calcareous clay, with nu- 

 merous impressions of deciduous leaves ; vast quantities of silicified 

 wood of greatest perfection and beauty are scattered all over the sur- 

 face. Some quite long trees and stumps were observed by the party. 

 The layers of growth were as perfectly shown as in any of our recent 

 woods. Upon the summit of the ridges or hills were beds of basalt as 

 usual. We have, then, a chaos here which it would be impossible to un- 

 ravel, except by tracing the formations from far distant points in their 

 continuity. The detritus is so thick and upon this grows such a luxuri- 

 ant vegetation, either grass or dense forests of pine, that the sediment- 

 ary rocks are exposed only here and there over restricted areas. We- 

 know, however, that up to the Grand Gaiion, and up the East Fork, for 

 fifteen miles, the Carboniferous, Jurassic, Cretaceous, and Tertiary groups 

 are represented more or less, although we can only catch glimpses of 

 them at rare intervals. We were traveling through this region in the 

 latter part of the month of July, and all the vegetation seemed to be in the 

 height of its growth and beauty. The meadows were covered densely 

 with grass, and flowers of many varieties, and among the pines were 

 charming groves of poplars, contrasting strongly by their peculiar en- 

 livening foliage with the somber hue of the pines. The climate was 

 perfect, and in the midst of some of the most remarkable scenery in 

 the world, every hour of our march only increased our enthusiasm. 



The climate cluring the months of June, July, and August, in this val- 

 ley, cannot be surpassed in the world for its health-giving powers. The 

 finest of mountain water, fish in the greatest abundance, with a good 

 supply of game of all kinds, fully satisfy the wants of the traveler, and 

 render this valley one of the most attractive places of resort for invalids 

 or pleasure-seekers in America. 



We will now descend the ridge in the more immediate valley of the 

 Yellowstone near the entrance of the East Fork, and not far from the 

 lower end of the Grand Canon. Our road is a rough one. The sediment- 

 ary rocks were crumpled into high, sharp, wave-like series of ridges. 

 From innumerable fissures, the igneous matter was poured out over the 

 surface which cooled into basalt ; and from these vents was also thrown 

 out, into the great lake, fragments and volcanic dust, which were arranged 



