94 STUART WELLER 



two regions which are at present wholly isolated from the main body 

 of the province, (i) at Lake Memphremagog near the international 

 boundary between Vermont and Quebec, and (2) southwest of James 

 Bay in Canada. In both of these regions the faunas recognized are so 

 like those of the Eastern Continental Province that there must have 

 been direct communication to them during the life of the faunas.' 



The Interior Continental Province is typically developed in Iowa, 

 where the Devonian strata are exposed from Muscatine County on the 

 Mississippi River, northwestwardly across the state into the southern 

 border of Minnesota, and it includes also the Devonian strata of Rock 

 Island and Calhoun counties, Illinois, and those of Central ^Missouri. 

 Beyond this the Devonian beds of Manitoba and the Mackenzie Valley 

 are to be included in this same province, which seems to be connected 

 in a northwesterly direction with the Eurasian Devonian Province. 

 The Western Continental Province is confined to the Great Basin 

 region, and its faunas are best known from the studies of Walcott^ 

 upon the Devonian faunas of the Eureka District in Nevada. 



Since the faunas of the Eastern Continental Province have a more 

 complete and continuous history than those of either of the other 

 provinces, and because they are much better known, their succession 

 is taken as the standard with which the other Devonian faunas of the 

 continent are compared. 



THE EASTERN BORDER PROVINCE 



For substantial additions to our knowledge of the Devonian faunas 

 of the Eastern Border Province we are recently indebted to Clarke,^ 

 although contributions of great importance were made many years ago 

 by the Canadian geologists, Logan and Billings. In this region the 

 Helderbergian and Oriskany faunas of Lower Devonian age have a 

 great development, and the faunas of the Gaspe basin give evidence 

 that this region was a center of dispersion of these two faunas. During 

 Middle Devonian time, in this same region, many of the Lower Devo- 



I For composition of the Lake Memphremagog fauna see Ami, Atm. Rep. Geol. 

 Surv. Canada, VII, N. S., 157J; also, Schuchert, Am. Geol., XXXII, 155. For James 

 Bay fauna see Parks, Ont. Bureau Mines, Report lor IQ04, Pt. I, pp. 180-91. 



' Monograph, U. S. G. S., Vol. VIII. 



3 "Early Devonic History of New York and Eastern North America," Mem. 

 N. Y. State Miis. Nat. Hist., Vol. IX. 



