Education Department Bulletin 



Published fortnightly by the University of the State of New York 



Entered as second-class matter June 24, 1908, at the Post Office, at Albany, N. Y, 



under the act of July 16, 1894 



No. 525 ALBANY, N. Y. August 15, 1912 



New York State Museum 



John M. Clarke, Director 

 Museum Bulletin 162 



THE LOWER SILURIC SHALES OF THE 

 MOHAWK VALLEY 



BY RUDOLPH RUEDEMANN 



INTRODUCTION 



While engaged in mapping the shales of the Saratoga and 

 Schuylerville quadrangles of the State of New York, the writer has 

 found that in order properly to correlate the formations of fossili- 

 ferous shales appearing there with the standard formations of the 

 State, it would be necessary to trace their relation to the Utica and 

 Frankfort shales through the Mohawk valley. In beginning this 

 task in Schenectady county, an unexpectedly large and interesting 

 fauna was found in the " Frankfort shale " of that county hitherto 

 considered as practically barren. This discovery promised a safe 

 conclusion as to the as yet unknown faunal and taxonomic relations 

 of the Frankfort shale to the Utica shale on the one hand, and 

 to the Lorraine beds on the other. The close faunistic and strati- 

 graphic relations of the Frankfort shale to the Utica shale were 

 early recognized in the work, and as the writer had previously 

 (title 6o\ page 44) obtained evidence of the different faunal aspect 

 of the " Utica shale " of the lower Mohawk from the typical shale 

 at Utica, it was found desirable to include the Utica shale in the 

 investigations. 



1 See Bibliography, p. 69. 



