1 88 NEW YORK STATE MUSEUM 



The Hamilton piscine fauna is so obviously the descendant of the preceding 

 Onondaga, and these two together have so much in common with the 

 Eifelian, Bohemian and Russian Mesodevonic, as to confirm in the strongest 

 possible manner the contention of Professors Clarke and Schuchert that the 

 Ulsterian and Erian should be recognized as divisions of the Middle 

 Devonic. 



Attention has been called by Professor Schuchert to the similarity 

 between the Middle Devonic fauna of the Hudson Bay region, and that of 

 the Mississlppian Onondaga. A number of considerations 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 moreover, they differ both in horizon and facies 

 from the Stringocephalus zone of western and northwestern Canada. It is 

 inferred, accordingly, 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 Mississlppian 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 propo- 

 sitions 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 descend- 

 ant 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.' 



' On the Faunal Provinces of -the Middle Devonic of America etc. Amer. Geol. 

 1903. 32:156-162. 



