Published monthly by the 



New York State Education Department 



BULLKTTN 408 



JULY 1907 



New York State Museum 



John M. Clarke, Director 



Bulletin in 

 GEOLOGY 13 



DRUMLINS OF 

 CENTRAL WESTERN NEW YORK 



BY 



H. L. FAIRCHILD 



PAGE 



Introduction : general description 391 



Areal distribution 394 



Orientation 399 



Relation to larger topography. . . 402 

 Relation to underlying rock strata 404 

 Form and dimensions 405 



Dimensions 410 



Composition and structure 412 



Rocdrumlins 413 



Concentric bedding 416 



Formation: theoretical mechanics 419 



a Dynamic factors pertaining 

 to the ice body 420 



b Factors relating to the drift 

 held in the ice 421 



c Factors of external control. . . 422 



Drumlin forms and observed 

 relations 422 



PAGE 



Relation to moraines 424 



Special features 425 



Syracuse island masses 425 



Montezuma island groups 426 



Nondrumlin areas: open spaces 426 

 Channels among thedrumlins. 427 



Summary 429 



Age of the drumlins 429 



Thrust motion of the ground 



contact ice 429 



Origin 431 



Dynamics 432 



Drumlin forms 433 



Depth of the drumlin-making 



ice 434 



Drumlins of Ireland 435 



Bibliography 436 



Index 441 



