400 NEW YORK STATE MUSEUM 



by west. This radial direction is shown on the general map, 

 plate I, and the smaller maps, plates 5 to 17, show the attitude and 

 forms within the 20 foot contours. 



The long axes of the drumlins indicate the direction of the latest 

 vigorous movement of the ice sheet in their locality, and the 

 variant directions of the drumlins throughout the whole area prove 

 a radial or spreading flow of the ice mass that rested in the Ontario 

 basin during the stage of waning which is represented by the 

 drumlin formation. 



This consonance of the drumlin attitude to the latest ice flow 

 direction is strikingly confirmed by the study of the drumlins in 

 outlying districts. The Chautauqua drumlins point southeast, in 

 harmony with the spreading flow of the Erian lobe of the wan- 

 ing ice sheet. On the other hand, the drumlins of the Water- 

 town district, east of Lake Ontario, point southwest, conform- 

 ing to the latest flow of the thinning ice in the StX,awrence 

 valley. 



Another interesting fact to be noted in this connection is that 

 the axial direction is not always uniform along the same meridian. 

 If the topographic control over the ice movement changed with the 

 varying latitude of the ice front, as the latter was receding, the 

 drumlins record that fact. For example, 20 miles south of Roches- 

 ter the ice margin w;as guided by the Conesus, Hemlock and 

 Honeoye valleys and the drumlins are north and south. But on the 

 same meridian, only 6 to 12 miles south of Rochester, the drumlins 

 point to the southwest, the ice margin being controlled by the f 

 Genesee valley and the thrust being from the northeast. 



The radial or spreading flow of the ice at any single stage must be 

 found by a comparison of the drumlin directions within a single 

 series of drumlins, that is, drumlins which were formed simul- 

 taneously. If we take the second, or Oakfield-Syracuse, series we 

 find the axial directions point as follows: At Oakfield, s. 55° to 

 60° w.; Fairport to Palmyra south ; Syracuse, s. 30° e. Taking the 

 third, or eastern Ontario, series, the drumlins are north and south at 

 Sodus bay; at Oswego, s. 30° e.; Mexico, southeast; Pulaski, 

 e. 20° s.; Sandy Creek, east. 



A peculiar confirmation of the genetic relation between drum- 

 lin attitude and ice-flow direction is found in the Pulaski region. 

 Passing northeastward around the corner of Lake Ontario (Mexico 



