88 



GEOLOGICAL SUBVEY OF THE TEERITOEIES. 



springs in relation to them. (Fig. 25.) The little stream on the east side is 

 one of the sources of Alum Creek, and the springs that border show the 

 origin of the alum that is held in solution in the waters, which hold their 

 full strength until they flow into the Yellowstone. We approached this 



Fig. 25. 





* ■» 



#%to 





'-■% 



■%., 



■ t-J" ^.'' W ^ 



Peet 



500 



^00 



SULPHUR AND MUD SPRINGS, CRATER HILLS, YELLOWSTONE RIVER, 8 MILES BELOW THE LAKE. 



group of springs on the west side, and the first spring that attracted our 

 attention was located at the base of one of the white hills. It was a pow- 

 erful steaui-vent, with the strong, impulsive noise like a high-pressure 



