FOURTH REPORT 07 THE DIRECTOR I907 53 



Attention has been called by Professor Schuchert to the similarity 

 between the ■Middle Devonic fauna of the Hudson Bay region, 

 and that of the Mississippian Onondaga. A number of considera- 

 tions are proffered to show that while each of these faunas has its 

 individual facies, yet both are of that type which characterizes the 

 American, in contradistinction to the Eurasian province ; and more- 

 over, they differ both in hx)rizon and facies from the Stringocephalus 

 zone of western and northwestern Canada. It is inferred, accord- 

 ingly, that the Hudson Bay Devonic area was entirely shut off from 

 communication with the Dakota sea, but on the other hand it is 

 thought probable that intermittent connection existed between the 

 former basin and the Mississippian sea. An opening is also posited 

 by the same writer, lasting throughout the Devonic, between the 

 Appalachian and Eurasian provinces, the route leading through the 

 so called Connecticut straits, thence along the Gulf of St Lawrence 

 and across the Atlantic. Having established what seems to him 

 a reasonable basis for the propositions just stated. Professor 

 Schuchert sums up his conclusions in regard to Middle Devonic 

 faunal distribution in the following paragraph : 



" The Onondaga fauna is the outgrowth of the Oriskanian fauna 

 of the North Atlantic type plus the migration during Onondaga 

 time of other North Atlantic forms by way of the Connecticut 

 trough and invasions from the far south through the Indiana basin. 

 The Hamilton fauna is the descendant of that of the Onondaga plus 

 North European migrants by way of the Connecticut trough, South 

 American arrivals by way of the Indiana basin, and slight invasions 

 from the Dakota sea by way of Traverse straits. These three 

 openings then remained in existence during the greater part of 

 Upper Devonic time." 



This rather full statement in regard to conceptual waterways has 

 been made not for the purpose of criticism, but in order to synthesize 

 as far as possible certain elements of apparently conflicting nature. 

 The test of a sound judgment is its ability to unify various and 

 sometimes even dissonant concepts. In the present instance it 

 becomes necessary to reconcile with the evidence furnished by 

 Helderbergian and Oriskanian invertebrates in favor of an invasion 

 from the northeast, certain other evidence that appears at first sight 

 discordant, namely, the failure of anv Lower Devonic vertebrates 

 to take part in the migration. As will be seen from an inspection 

 of the faunal lists, the abundant and rather diversified fish 

 fauna occurring in the synclinal basin of the Rcstigouche 

 near Campbellton, N. B., is without a single representative 

 in rocks of Lower or Middle Devonic age in the Appalachian 

 province. No traits are observed in the Onondaga or Hamilton fish 

 faunas which can be ascribed to an immigration from eastern 

 Canada by way of the putative water route called by Clarke the 

 "Appalachian strait," and by Dana the " Connecticut trough," which 

 is supposed to have been open during the late Siluric and greater 

 part of the Devonic. None of the Appalacin'an Mesodevonic verte- 

 brates can be regarded as the genetic descendant of forms that 



