NO. 2 



SMITHSONIAN EXPLORATIONS, 1924 



21 



do into sharp, steep peaks more than 7,000 feet above the deep 

 Jackson Lake. A dam has been built at the former outlet of the lake, 

 impounding the flood waters to a depth of 39 feet, thus preserving 

 an enormous quantity of water for irrigation in the Snake River 

 Valley, 300 miles away. The Teton Mountains, due to their rugged- 

 ness, and the extensive lakes at their base, proved more than ordinarily 

 difficult to work from an, automobile. They present, however, many 

 interesting and some unique geological problems. This range con- 

 sists of highlv tilted Archaean rocks on the eastern face overlain from 



Fig. 28. — \'ie\v south from Glen Eyrie, Colorado, showing the strata 

 folded during building of Rocky Mountains, now weathered into upright 

 forms. Garden of the Gods visible in distance. (Photograph by Resser.) 



the west by mtich less steeply inclined strata which include Cambrian, 

 Ordovician and younger series. A six-inch layer of relatively pure 

 iron ore was observed near the base of the Cambrian series. At all 

 points in the range visited this season it was found that the fossils had 

 also been broken before being buried. 



The highway across Teton Pass, by which one leaves Jackson Hole, 

 going south and west proved exceedingly steep but highly interesting 

 and of great beauty. The drainage of Jackson Hole escapes through 

 the Grand Canyon of the Snake River, cut more than a half mile 

 deep into the mountain wall closing in the south end of the valley, for 

 which reason the road cannot follow along it. 



