632 NORTH AMERICAN INDEX FOSSILS. 



Middle Devonic. 



Cedar valley limestones 100 ft. 



Wapsipinicon limestones and shales. . .60-75 f^- 

 Upper Davenport. 



Lower Davenport (Fayette breccia). 

 Independence shales. 

 Otis beds. 

 Coggan beds. 



{Hiatus and dis conformity.) 



SUBFORMATION. 



Lower Siluric (Niagaran). 



Upper Devonic beds related to those of Iowa are widely dis- 

 tributed over northwest Canada, and are again known in the Rocky 

 Mountain region and westward. In northwestern Colorado the 

 Elbert formation and the lower two thirds of Ouray limestone 

 represent the Devonic. The upper part of the Ouray is of Mis- 

 sissippic age. In the Grand Canyon region, the Temple Butte 

 limestone represents a part of the Devonic. 



In Arizona (Bisbee region) the Devonic is represented by the 

 Martin limestone resting disconformably upon Cambric limestone. 

 In the Wasatch Mountains, a part of the Wasatch limestone prob- 

 ably represents late Devonic, though most of it is Mississippic. 

 Finally, in Nevada (Eureka district) the Nevada limestone, 6,000 

 ft. thick, is partly at least of Devonic age. The succeeding White 

 Pine shales, which have also been placed in the Devonic, are re- 

 garded by some as of later age.^^ 



In southeastern Alaska, the Vallenar series of limestones is in 

 part at least Devonic. In Prince Williams Sound and the lower 

 Copper River Basin, the Nikolai greenstone or basalt may be of 

 Devonic age. In the upper Copper and upper Tanana basins, the 

 Wellesley and Chisna groups of conglomerates and shales and the 

 Titelna volcanics are of Devonic age. Finally, the Rampart series 

 of the middle and lower Yukon regions and a part of the Fickett 

 series of northern Alaska, are referred to the Devonic. 



'^See Girty, Bull. U. S. G. S., 377, P- 10, footnote. 



