T. B. Comstock— Geology of Western Wyoming. 431 
rugged range of volcanic origin east of the Yellowstone Basin, 
have cut narrow cafions through this material for a distance of 
more than seventy-five miles, affording rare opportunities for 
the study of the effects of subterranean forces. The great 
mass of the range is made up of a volcanic breccia, with 
I can make a more complete study of notes and specimens. 
an special pains to observe, and collect as much mate- 
mal as Epessible in this department, and I believe that I have 
‘ueceeded in obtaining much valuable information by this 
ag agate, the deposition of the so-called ‘ alkali,” and the 
t cation of the immense pace’ of “petrified” wood in 
aba have thus been collected, besides a mass of material 
‘apes 3 the erosion and weathering of the rocks, and the 
. affecting or affected by the physical geography of the 
Shon = One fact, which I consider of much importance, 1s the 
of th ance of ozone in the atmosphere, to which I trace much 
ma eatin reddening of many of the yellow and brownish 
hes containing iron. 
veh a se s within * oe 
i eee: tt is th note that the Stinking Water 
Ehowes Win ‘ I refer in this Sapte, fa, the wacrtant, SRST of the Big Horn 
Which bears Be iver, by that name, and not the tributary of Jefferson River, 
Same name, 
