DRUMLINS OF CENTRAL WESTERN NEW YORK 399 



Chautauqua lake, with direction pointing southeast [pi. 21]. 

 Another group occurs about the north end of Cazenovia lake, 

 with altitude' up to 1400 feet. Scattering drumlins occur in many 

 localities, and probably at even higher altitudes than noted above. 



The amount of land surface included in the principal drumlin 

 area is roughly estimated as 2500 square miles without including the 

 portion east of Lake Ontario. 



Some of the peculiarities of the main drumlin series, the Oakfield- 

 Syracuse, in the matter of definite boundaries and minor grouping 

 should be noted here. These features, though difficult of verbal 

 description, appear very striking on a large map made by joining 

 the topographic sheets. Along the northern border of this series 

 from Sodus east to Irondequoit depression the drumlins are quite 

 abruptly replaced bymorainic topography [pi. 15], the relationship 

 being discussed later [p. 424]. The north border of the eastern 

 Ontario series shows the change from drumlins to moraine even more~ 

 plainly [pi. 6]. 



On the southern borders the drumlin topography sometimes 

 shades off into smooth drift [pi. 13], while in other districts it is 

 lost in the bolder relief of the rock hills [pi. 16]. 



The most abrupt ending of the drumlin topography is along the 

 courses of ancient glacial river drainage. A series of drainage 

 channels marks the definite southern limit -of the second drumlin 

 series from Victor to Geneva, and on the west of the Genesee at 

 Leroy and Mumford. A later drainage course, from Fairport to 

 Syracuse, traverses the heart of the drumlin series, and seems 

 responsible for the isolation of minor groups, the peculiar forms of 

 which are indicated in plates 9 to 12. 



Orientation 



The attitude of the drumlins with reference to compass direction 

 varies according to their position in the area. The angular 

 directions of their longer axes cover nearly a half circle. In the 

 district east of Lake Ontario they point east, that is they were 

 shaped by a movement of the ice from the west. As we pass west- 

 ward around the south side of Ontario we find the direction 

 gradually shifting to southeast, then to south, and finally in western 

 New York to southwest ; while on the Niagara-Genesee prairie, 

 in the northwest part of the State, the direction is southwest 



