452 J. E. WOLFF^ — GEOLOGY OF THE CRAZY MOUNTAINS. 



movements of the crust have removed or altered many of the original 

 features* 



The existence of this high range as an outlier is due to the facts that it 

 was the center of violent eruptive activity in post-Cretaceous time, and 

 that the presence of great masses of crystalline rock, combined with the 

 honeycombing of the soft strata by dikes, enabled the whole mass to 

 resist the erosion which levelled the adjoining country. The moderate 

 uplifting of some of the larger sheets with their enclosing- rocks also con- 

 tributed to this result. Warren Upham calls it a striking example of 

 the "eroded mountain range." t 



It is hoped this sketch may present the claim of these mountains as a 

 grand geological model and one. for the Rocky mountains, easily acces- 

 sible. From Livingston or adjoining stations on the Northern Pacific 

 railroad it is an easy day's drive to the foot of the range; the canyons of 

 the larger streams on the east side are easily accessible by horseback and 

 at the entrance even by wagon, and it is possible to ride to the falls in 

 the contact zone. The outlying theralite buttes can all be visited by 

 wagon. 



*A smaller l>ut apparently similar stock was observed in the northern half of the range, but not 

 studied in detail. 

 f A Classification of Mountain Ranges, etc. A.ppalachia, vol. vi, no. •'!. 1891, p, 204. 



