DEVONIAN AND MISSISSIPPIAN FAUNAS 259 
two regions which are at present wholly isolated from the main body 
of the province, (1) 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 vears 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- 
« For composition of the Lake Memphremagog fauna see Ami, Ann. Rep. Geol. 
Surv. Canada, VII, N. S., 157J; also, Schuchert, Am. Geol., XXXII, 155. For James 
Bay fauna see Parks, Ont. Bureau Mines, Report for 1904, Pt. I, pp. 180-91. 
2 Monograph, U.S. G.S., Vol. VIII. 
3 ‘Early Devonic History of New York and Eastern North America,” Mem, 
N.Y. State Mus. Nat. Hist., Vol. IX. 
