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. 445 ALBANY, N. Y. April 15, 1909 



New York State Museum 



John M. Clarke, Director 

 Museum bulletin 128 

 GEOLOGY OF THE GENEVA OVID QUADRANGLES 



BY 



D. DANA LUTHER 



The geologic map of the Geneva and Ovid quadrangles covers 

 an area of 455 square miles in the heart of the Finger Lakes region 

 of central New York. 



A part of this area embracing about 100 square miles lying to 

 the north of Seneca lake and Seneca river is a low, flat, alluvial 

 region diversified with many kames and drumlins, conical or oblong 

 hills of sand and gravel that rarely reach a hight of more than 100 

 feet and are usually much lower. 



In this region the soft red Vernon and gray Camillus shales that 

 succeed the Medina sandstones and Lockport dolomites at the north 

 were excavated during the glacial epoch to considerably greater 

 depth than those harder rocks, thereby producing a broad shallow 

 depression that extends eastward from Ontario county to Onon- 

 daga county, and through which the waters from a large part of 

 the Finger Lakes drainage area reach Lake Ontario by way of the 

 Seneca and Oswego rivers. The northern part of the Geneva 

 quadrangle lies in this depression and although possessing features 

 of extraordinary interest to the student of glacial geology is wholly 

 devoid of rock outcrops by which the contact lines of the geologic 

 subdivisions can be located. The area lying south of the Seneca 

 river, however, presents entirely different characteristics as it lies 

 on the sloping northern edge of the great New York plateau 

 against which the ice sheet here spent a large part of its erosive 

 force in deepening and enlarging the old preglacial depressions, 

 now the Seneca lake and Cayuga lake valleys, to their present 

 depth and size, leaving a broad separating ridge between them. 



