52 NEW YORK STATE MUSEUM 



It is very necessary to understand this matter of the provincial 

 character of Devonic faunas in North America. Also, in tabulating 

 the facts of distribution, one must keep in mind the inferred lines of 

 intercommunication between those provinces that were connected, 

 as well as the position of barriers between others that are known to 

 have been separated. The data upon which our information in 

 regard to these matters reposes have been brought together chiefly 

 by workers in invertebrate paleontology, and as the evidence at 

 their disposal is enormous as compared with that obtained from a 

 study of the vertebrates alone, no deductions drawn from the latter 

 are likely to prejudice the results depending upon a different class 

 of remains. In point of fact, no discoveries of fossil fishes have 

 yet been made which tend to contradict or discredit conclusions 

 already established on the basis of fossil invertebrate evidence. 

 The known distribution of the former is in all respects consonant 

 with, and one is tempted to add, confirmatory of the principles that 

 have been formulated from a study of the latter. We find simply 

 that the more mobile free-swimming contingent of Devonic faunas 

 followed the same routes and penetrated, probably with greater 

 facility, into the same areas as the slower moving invertebrate 

 associates of the original fauna, wherever we are able to trace its 

 migrations. 



Nevertheless, some facts relatingf to the distribution of Devonic 

 vertebrates stand out with such distinctness as to attract particular 

 attention. The earlier Devonic horizons in New York State are 

 singularly deficient in fish remains, and the faunas that appear suc- 

 cessivelv in the Meso- and Neodevonic are introduced with little 

 or no foreshadowing, save that the members of the Hamilton fish 

 fauna are largely a residuum or evolution product of the preceding 

 Onondaga congeries. Clearly, however, the Mesodevonic fish 

 faunas are not indigenous in the Appalachian basin for we meet 

 with practicallv the same assemblage in rocks of equivalent age 

 elsewhere, as for instance, in the Eifel district (Calceola beds) and 

 Bohemia (etages F^ and G^-G^) ; and besides, the Oriskanian fauna 

 contains no elements, so far as known, out of which the Onondaga 

 might have developed. The vertebrate portion of the latter is, 

 therefore, quite unmistakably an immigrant fauna. That it did not 

 come in from the northeast may be asserted with equal confidence, 

 for none of its members are represented in the maritime provinces 

 of eastern North America, nor indeed, in the Lower Old Red sand- 

 stone of North Britain, Greenland or Spitzbergen. As in the 

 case of the majority of invertebrates, the Onondaga fish fauna came 

 in from the west, and in course of time very probably withdrew 

 westward, many of its characteristics persisting into the Hamilton 

 of the western interior province. The Hamilton piscine fauna is 

 so obviously the descendant of the preceding Onondaga, and these 

 two together have so much in common with the Elfelian, Bohemian 

 and Russian Mesodevonic, as to confirm In the strongest possible 

 manner the contention of Professors Clarke and Schuchert that the 

 Ulsterlan and Erian should be recognized as divisions of the Middle 

 Devonic. 



