172 



EEPORT UNITED STATES GEOLOGICAL SUEVEY. 



being 196or. The springs were not mapped with sufficient accuracy to 

 identify them all, but the following gives the comparison of the tempera- 

 ture of those that are undoubtedly the same springs : 





1871. 



1878. 





© 



« 

















Spring. 



43 g 



s , 



■g.a 



t.i 





















<v 





p,a! 



p^'-s 



ftm 



f^V. 





y's 



8 = 



S=t; 



a* 





o 









H 



H 



H 



H 





OF. 



°F. 



°F. 



°F. 



"No. 4, Fortress 



196 



70 



201 



48 



Ifo 86 



191 

 166 

 183 

 161 



70 

 70 

 70 

 70 



186 

 161 

 200 

 162 



53 





53 



Ko. 88 



58 



No. 89 



58 





196 



70 



199 



51 







On the accompanying map of the Lower Geyser Basin, only the num- 

 bers of the most important springs are given, especially on the east side 

 of the river. 



GOOSE LAKE MUD SPRINGS. 



These mud springs are situated near a small lake or pond (named 

 Goose Lake in 1872) a small distance east of the active boiling springs 

 of the Eiver Group. There are from 30 to 50 springs in the group, 

 which are of all sizes from a few inches to 20 or 30 feet in diameter. 

 They are boiling, sputtering, and spouting springs, in which the mud is 

 of all consistencies, from that of a simply turbid or muddy water to 

 that of stiff mortar. The colors are white, brown, and lead-colored 

 blue. Some of them are deep pits 15 to 20 feet in depth, at the bottom 

 of which the mud sputters and spurts at times above the rims of the 

 craters. One of these, near the lake, is nearly forty feet in diameter 

 and is in constant action. Surrounding it are a number of small mud 

 cones, 4 inches to a foot in height, which keep up a simmering noise. 

 They are steam vents, and on breaking them open they are seen to be 

 streaked with sulphur and iron stains. Some of them are lined with 

 crystals of sulphur. Sulphur is found at one other locality in the Basin, 

 but is more prominent here, although not nearly so abundant as at many 

 of the localities on the Yellowstone. 



SEVENTH GROUP OR FAIRY FALL SPRINGS. 



Under this head I include all the springs found along the course of 

 Fairy Fall Creek, although they are readily divisible into two groups. 

 The creek is named from the fall at the head of the valley called Fairy 

 Fall by its discoverer. Colonel Barlow, who determined its height to be 

 250 feet. The creek rises in the plateau south of Twin Buttes and 

 turns around them, flowing a little east of north for about 4 miles to the 

 Fire Hole, which it joins a short distance above the mouth of Sentinel 

 Creek. 



On the south side of the buttes there are some springs in the timber, 

 their presence being revealed by the columns of steam. They were 

 not visited, and I cannot, therefore, present any description of them. 



The principal springs are out in the open valley. The upper sub- 

 group comprises the si)rings included under Nos. 1 to 15, most of them 



