DEVONIC FISHES OF THE NEW YORK FORMATIONS 1 87 



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, con- 

 firmatory 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 relating to the distribution of Devonic verte- 

 brates 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 successively 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 Meso- 

 devonic fish faunas are not indigenous in the Appalachian basin, for we 

 meet with practically the same assemblage in rocks of equivalent age else- 

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

 (etages F^ and G'-G^) ; and besides, the Oriskanian fauna contains no ele- 

 ments, 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 sandstone 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. 



' Clarke, J. M. Indigene and Alien Faunas of the New York Devonic. N. Y. State 

 Mus. Bui. 52. 1902. p. 668. 



