POST-CRETACEOUS HISTORY OF WESTERN WYOMING 321 



led to think that the three systems have had somewhat different 

 histories. Along Wind River and Owl Creek the streams are now 

 generally intrenched 10-30 feet below the gravel-strewn terrace of 

 the Lenore cycle, and widened according to circumstances. This 

 has been accomplished in post-glacial time. 



Fig. 39. — Crow Creek valley and Crowheart Butte, showing the broad Circle 

 plain, beneath which the modern valley has been cut, surmounted by a monadnock 

 carrying a remnant of an older plain. (Drawn from a photograph.) 



Fig. 40. — Dry Creek valley in the Wind River basin. It illustrates the dissection, 

 in the Lenore cycle, of the plain of Circle. The beds dip 10-15° away from the camera. 

 The valley in the center of the view is about 150 feet deep. (Photographed by D. D. 

 Condit, U.S. Geological Survey.) 



Quaternary glaciation. — ^All of the mountain ranges of the dis- 

 trict that exceed 10,000 feet in elevation bear marks left by valley 

 glaciers of an earlier time. Indeed, a few small bodies of ice still 

 exist in the deep cirques of the Teton, Shoshoni, and Wind River 

 ranges. By glacial action the mountain crests have been exca- 

 vated in the characteristic way, and the canyons have been modified 



