POST-CRETACEOUS HISTORY OF WESTERN WYOMING 117 



recently been made by Mr. Hyrum Schneider, and recorded in his 

 manuscript thesis for the M.A. degree at the University of Wiscon- 

 sin in 191 1 (not pubHshed) . He concludes that the Middle Miocene 

 disturbance affected all of the Cordilleran region, being expressed 

 as folding along the Pacific coast and in Washington, but chiefly 

 by warping and faulting in the Rocky Mountain province. 



To summarize these considerations, it may be said then that 

 the sedimentary formations deposited in the early part of the 

 Tertiary period were afterward very gently folded and broken along 

 a few scattered normal faults (see Fig. 11), and that the event took 

 place in the midst of Tertiary time and probably in the middle of 

 the Miocene epoch. Inasmuch as the Tertiary beds almost every- 

 where dip away from the anticlinal ranges and toward the syn- 

 clinal basins, it seems evident that the mid-Tertiary deformation 

 merely emphasized the structures produced at the close of the 

 Cretaceous. The faults do not, however, in all cases follow these 

 older structures, for in the Teton Range the original Gros Ventre 

 anticline, which had a northwest-southeast trend, is diagonally 

 transected by several large north-south faults. 



[To be continued] 



