NAPLES FAUNA IN WESTERN NEW YORK, PART 2 .2 11 



the province, the other following in its train, which did not attain a point 

 so far east. We have elsewhere defined the earliest or prenuncial appear- 

 ance of* the western fauna in the Genundewa or Styliola limestone of 

 the Genesee shales, an appearance coextensive with the entire province 

 from Yates county to Lake Erie. Even farther to the east in Seneca 

 county where the Genundewa limestone is not present, there is a higher 

 horizon near the top of the Genesee shales where this fauna is present. 1 

 Thus the species which traveled farthest have sometimes left their traces 

 behind over the whole area, in other instances have developed fruitfully 

 only when reaching the eastern region. On the other hand, most species 

 of this rear guard never penetrated the easterly region. The whole fauna 

 of the Genesee province is knit together by its biologic limitations, its 

 evident deep water habit, the community of generic character among 

 unlike species, its appurtenance, in eastern and western expression alike, 

 to the fauna with Mantic. intumescens and its remarkable simi- 

 larity with transatlantic manifestations of that fauna. It is with the species 

 of this Genesee province that we are in these particulars, here alone 

 concerned. 



Consideration of the tables given at the end of the book will show our 

 present knowledge of the geographic distribution of the members of this 

 fauna and indicates how well founded are these differences in their dissemi- 

 nation. We have therefore on this basis observed the evident existence of 

 two subprovinces of the Genesee province : 



Naples subprovince; at the outset covering the entire extent of the prov- 

 ince but subsequently closely restricted to the eastern region ; during most 

 of its existence approximately bounded on the east by the meridian of 

 Cayuga lake, and on the west by the Genesee river. 



Chautauqua subprovince; the western region ; extending from the Genesee 

 river to Lake Erie and nearly to the western state line ; of later date than 

 the opening stages of the Naples subprovince. 



'Clarke. N. Y. State Geol. 14th An. Rep't. 1895. p. 100. 



