GEOLOGICAL SURVEY OF THE TEEEITOEIES. 



99 



Fig 



mountain, and the rounded form of the summit, it Las received the 

 name of the Elephant's Back. Obsidian, volcanic breccia, and trachyte 

 constitute the varieties of rocks for the most part. The general 

 elevation is about 10,000 feet. There are no streams of any size flow- 

 ing into the lake on the west side, and therefore tliere are no depres- 

 sions of any importance in the rim that would form passes over the 

 divide. It is around the lake and among the mountains that border it 

 that we encounter the most formidable impediments to traveling. The 

 autumnal fires sweep among the dense pine forests, and the winds then lay 

 them down in every possible direction. Sometimes a perfect net-work, 6 feet 

 in height, is formed of these tall pines, wdiich are 100 to 150 feet in length, 

 and it was with the utmost dilhculty that we could thread our tortuous 

 way among them. We attached a pair of shafts 

 to the fore- wheels of one of our ambulances for 

 the odometer, and these were probably the first 

 wdieels that ever were taken into this little-known 

 region. The labor of taking this single pair of 

 wheels over such a country was extremely great, 

 both for the man who managed them and the 

 animal that drew them. Sometimes this fallen 

 timber will extend from five to ten miles con- 

 tinuously. (Fig 33.) We adopted the plan of 

 making peimanent camps at different points 

 aiound the lake while explorations of the country 

 ill the vicinity were made. Onr second camp 

 was pitched at the hot springs on the southwest 



arm. This])osition 

 comnuinded one of 

 the finest views of 

 thelakeand its sur- 

 roundings. While 

 the air was still, 

 scarcely a ripple 

 could be seen on 

 the surface, and the 

 varied hues, from 

 the most vivid 

 green shading to 

 ultramanne, pre- 

 sented a picture 

 that would have 

 stirred the enthu- 

 siasm of the most 

 fastidious artist. 

 Sometimes in the 

 latterportion of the 

 day a strong wind 

 would arise, ai'ous- 

 ing this calm sur- 

 face into waves like 

 the sea. Near our 

 camp there is a 

 thick deposit of the 

 has been worn by the waves into a bluff wall 25 feet 

 high above the water. It must have originally extended far out 

 into the lake. The belt of springs at this place is about three miles 



TRAVELING IN THE YELLOWSTONE COUNTRY. 



silica, which 



