54 



G. R. Mansfield — Triassic and 



composed of three formations 3 , but these subdivisions 

 cannot well be differentiated throughout southeastern 

 Idaho. 



The Nugget sandstone, which overlies the Wood shale 

 and was formerly considered Triassic or Jurassic, is 

 now referred to the Jurassic. 



Fig. 1. Index map: 1, Fort Hall Indian Reservation; 2, Montpelier; 

 3, Slug Creek; 4, Crow Creek; 5, Lanes Creek; 6, Freedom; 7, Henry; 

 8, Cranes Flat; 9, Park City District; 10, Southwestern Wyoming (Veatch, 

 Prof. Paper 56). 



3 Mansfield, G. E. : The geography, geology, and mineral resources of the 

 Fort Hall Indian Reservation, Idaho, U. S. Geol. Survey Bull. 713, in press. 



