NAPLES FAUNA IN WESTERN NEW YORK 



PART 2 



BY 



JOHN M. CLARKE 



INTRODUCTION 



This memoir is in continuation " of studies of the events, biologic and 

 physical, of Portage time in the State of New York. Previous publications 

 on this subject have been for the most part of more preliminary character ; 

 but the nature of the fauna of that provincial element of the Portage 

 region which occupied the New York sea westward of the present meridian 

 of Cayuga lake (Intumescens zone or Naples shales) was taken up for 

 special consideration in the first instalment of this memoir which was 

 devoted to the Goniatitinae. We here propose to treat specially of the 

 lamellibranchs, gastropods and pteropods of this provincial fauna and to 

 present therewith such considerations as have developed from a continued 

 study of the relation of these organisms to their environment 



The sea of Portage time 



The great mediterranean sea (Appalachian gulf) which spread over 

 the southern parts of western, central and eastern New York during this 

 opening period of late Devonic time (stratigraphically the lower Upper 

 Devonic) was depositing tremendous quantities of sand commingled with 

 mud, throughout its entire extent. This gulf was bounded on the north by 

 a coast line whose exact position we can not locate, because the shoreward 

 edges of the bottom deposits have been worn away. There are certain 

 factors indicating that during some portion of the time its western arm was 

 well northward to, and beyond the latitude of Lake Ontario, for the heavy 

 beds of bituminous shales which formed at the base of the series (Genesee 

 shales and black bands of the Naples beds) and which in the western sec- 

 tions attain relatively great thickness, are to be probably regarded as point- 

 ing to deposition in deep water. This interpretation would be in accord- 



*Part i of this discussion of the Naples fauna was published in the 16th An. Rep't' 

 of the State Geologist. 1898. p. 29-161, pi. 1-9. 



