NIAGARA FALLS AND VICINITY T27 



statement, that the New York fauna is more individuahzed, show- 

 ing characteristics stamping- it in some degree as a provincial fauna. 

 The Niagaran fauna of the central states however is more closely 

 allied to the European Mid-Siluric fauna than to that of Xew York 

 state, from which we may conclude that the pathway of communi- 

 cation between the American and European Siluric seas was not by 

 way of New York, a conclusion which is in entire harmony with 

 those derived from the physical development of this region and the 

 characteristics of the strata. 



Welleri has collected data which indicate that the pathway of 

 migration of faunas between the two continents was by way of the 

 arctic region. According to Weller's interpretation of the facts, there 

 existed in North America during Siluric time ''. . . a north polar 

 sea with a great tongue stretching southward through Hudson bay 

 to about latitude 33°. There were doubtless islands standing above 

 sealevel within this great epicontinental sea; and at the latitude of 

 New York there was a bay reaching to the eastward, in which the 

 Siluric sediments of the New York system were deposited. Labra- 

 dor, Greenland and Scandinavia were in a measure joined into 

 one great land area, though perhaps with its continuity broken, with 

 a sea shelf lying to the north of it and another to the south. An- 

 other epicontinental tongue of this northern sea extended south into 

 Europe, bending to the west around the southern part of the Scan- 

 dinavian land and connecting with a Silurian Atlantic ocean. The 

 sea shelf to the north of the Labrador-Scandinavian land was a 

 means of intercommunication between northern Europe and the in- 

 terior of North America, and the sea shelf to the south of this land 

 was a pathw^ay between England and eastern Canada." That por- 

 tion of North America lying to the west of a line drawn from the 

 Mississippi to the Mackenzie appears to have been dry land during 

 the Niagara period, and connected with the Appalachian land on the 

 east by the westward trending axis of the latter in the southern 

 United States. 



At the close of the Niagara period, there appears to have been an 

 elevation of the continent which converted the Bay of New York 



'Nat. hist. sur. Chicago acad. sci. bul. 4 and Jour. geol. 4:692-703. 



