I04 STUART WELLER 



beds younger than the HamiUon; the remaining species are common 

 to the Onondaga and the Hamilton, with one exception, which occurs 

 in the Hamihon and the Chemung. From these figures it is evident 

 that this Great Basin fauna contains a strong Onondaga element, 48 

 species in all. Of the Hamilton species neither Tropidolepius cari- 

 natus,^ Chonetes coronatus, nor any of the strictly foreign species in the 

 fauna are recognized, the entire Hamilton element being of that associa- 

 tion which seems to have originated from the Onondaga. Of the three 

 highly characteristic elements of the Onondaga fauna of the East, 

 corals, cephalopods, and fishes, we find 11 species of corals and 11 

 species of cephalopods, but none of the latter are identical with those 

 of the East, although they are congeneric. Of icthyc remains but a 

 single tooth was collected by Walcott, but in the Kanab Canon of 

 northern Arizona a strongly marked Devonian fish horizon is recorded,^ 

 although the composition of the fauna has not been made known. 



In its entirety the Devonian fauna of the Western Continental 

 Province may be said to be composed of a combination of two distinct 

 elements : (i) the Middle Devonian fauna of the Eastern Continental 

 Province, exclusive of the southern hemisphere element in the Hamil- 

 ton, and (2) the fauna of the Interior Continental Province. These 

 two elements are not fully differentiated in the faunas, since species 

 from the lowan or Mackenzie Basin faunas occur indiscriminately in 

 either the lower, middle or upper divisions of the Great Basin Devo- 

 nian. The Onondaga element also occurs through all of the divisions, 

 although it is most conspicuous in the lower beds. Within this prov- 

 ince there is no faunal evidence indicating the presence of Devonian 

 rocks of greater age than the Onondaga, but sediments were doubt- 

 less deposited in the area contemporaneously with the Onondaga, 

 Hamilton, and Upper Devonian of the Eastern Continental Province, 

 but no beds can be correlated definitely with either of the eastern 

 formations. The older of the beds are doubtless of greater age 

 than the oldest Devonian beds of Iowa, although they may not be 

 older than some of those of the Mackenzie Valley. 



1 Tropidoleptiis carinatus has been recorded from the Pinon Range, Nevada, 

 but the species has not been figured, and the identification has not been confirmed, 

 Monograph, U. S. G. S., VIII, 276. 



2 Walcott, Monograph, U. S. G. S., VIII, 7; also Am. Jour. Sci. (3), XX, 225. 



