EARLY DEVONIC HISTORY OF NEW YORK AND EASTERN NORTH AMERICA 25 I 



Gaspe basin was a center of dispersion of these two faunas and that the 

 direction of this dispersion so far as the facts now indicate was still toward 

 the southwest. 



The Gaspe sandstone presents a very different condition. In this 

 fauna of about 50 species so far as registered, one seventh to one sixth are 

 survivors of the Oriskany element in the Grande Greve limestones. With the 

 Hamilton faunas from the calcareous shales of the Skaneateles, Moscow and 

 Ludlowville formations of New York, this Gaspe sandstone fauna presents 

 a predominant agreement, having 16 identities and 6 affines, or approach- 

 ing fifty per cent of the fauna. This very interesting condition seems to 

 indicate an invasion of the later fauna from the west, while the earlier 

 Oriskany-Helderberg fauna was still occupying the ground. The interval 

 represented in the Appalachian gulf by the deposition of the Schoharie grit 

 and Onondaga limestone and other closely allied faunas is not differentiated 

 in Gaspe but there is a positive forecast of this fauna among the Grande 

 Gr^ve fossils. Thus there are here 13 identities and 12 faunas with Onon- 

 daga species. The Onondaga fauna therefore is here one of the undiffer- 

 entiated elements of the autochthonous Grande Greve fauna. Several of its 

 members bear distinctive marks of primitive structural condition to be per- 

 fected only in the later stage of differentiation when the fully matured 

 Onondaga fauna held its place in the orderly and refined succession in the 

 New York field. 



The evidence is thus fairly cumulative that the Gaspe basin was an 

 area of rapid evolution during the early Devonic and a center of dispersion 

 from which the lines of immigration departed westward. We can not now 

 say that they did not also lead thence eastward. In a later Devonic stage 

 this basin was the recipient of migrants from the west. The course of 

 migration into and out of the interior Appalachian waters was along a sea- 

 way which can not yet be traced step by step, but evidently parallel to the 

 Appalachian folds. There seems now a fair presumption of a continuous 

 connection between the Gaspe basin and the east by way of the Connecticut 



