New York State Education Department 



New York State Museum 



John M. Clarke Director 



Bulletin go 



PALEONTOLOGY 14 



CEPHALOPODA OF THE BEEKMAN- 

 TOWN AND CHAZY FORMATIONS 



OF THE 



CHAMPLAIN BASIN 



BY 



RUDOLF RUEDEMANN 



PREFACE 



The faunas of the older New York formations have never re- 

 ceived adequate consideration. The invaluable determinations made 

 by Prof. James Hall in the first volume of the Palaeontology of 

 New York were based on the material collected chiefly from the 

 central and western skirts of the Adirondacks during the progress 

 of the geological survey of 1836-43 or brought together from still 

 older collections belonging to private individuals or to the Albany 

 Institute. Although this great work laid the foundation of all our 

 knowledge of these early faunas in America yet as the years passed 

 on its distinguished author realized its incompleteness. The Siluric 

 region of the Lake Champlain basin was then an unopened field 

 to the paleontologist. The profusion of its fossil remains, which 

 far exceed in abundance those of the region from which the origi- 

 nal collections were assembled, was not recognized and it was not 

 till the later years of Professor Hall's long life that explorations 

 in this basin began to reveal the inadequacy of his early work. It 

 was one of his unrealized purposes of this later period to revise 

 and amplify the volume referred to. Though it did not fall to 

 him to see this important work executed yet he may be credited with 

 having initiated the undertaking. Explorations having for their 

 end a more exact knowledge of the stratigraphy of the region w ere 

 inaugurated by him and at his instance Professors J. F. Kemp and 

 H. P. Gushing commenced their study of the geology of Essex and 



