402 NEW YORK STATE MUSEUM 



in some areas, as north and west of Pulaski, the moraine character 

 prevails. Frequently a drumlin form as viewed from some distance 

 becomes irregular and morainal in minor relief on nearer view. 

 Sometimes the moraine surface is equally puzzling ; smooth ridging 

 or ribbing making one doubtful whether to map the area as moraine 

 or drumlinized drift. Such areas occur southwest of Pulaski [pi. 5] 

 and northwest of Sandy Creek. 



One important point which has a bearing on the origin of drum- 

 lins should be noted here. The secondary or contrawise forms 

 do not seem to have been made by the cutting or carving of the 

 primary forms ^but to have been produced by the addition or plaster- 

 ing on of the later form. The work seems to have been con- 

 structional, not erosional. 



The explanation of these exceptional features would seem to be 

 that the main and larger drumlin forms were made by the eastward 

 motion of the ice ; and that the minor molding, at a high angle and 

 usually southward, was produced when the waning ice in this 

 district felt directly the thrust from the St Lawrence valley. It 

 does not appear that the molding of the drift is pronounced in 

 directions intermediate between eastward and southward. Possibly 

 while the ice flow was changing from eastward to southward it was 

 not relatively so vigorous, but it is more probable that only the latest 

 of the minor ridging is conspicuously preserved. 



Relation to larger topography 



A glance at plate 1 shows that the general drumlin area covers 

 ground of all altitudes from the level of Lake Ontario (and they 

 probably occur in the depths of Ontario) up to about 1700 feet; 

 this highest edge of the drumlin belt lying west of Canan- 

 daigua lake [pi 16]. West of the Seneca valley they usually reach 

 up to high ground, 1100 to 1500 feet. In the low north and south 

 depression of the Seneca and Cayuga valleys, where we might 

 expect them to be well developed, they are weak or wanting above 

 500 or 600 feet [pi. 3, fig 2]. While scattering drumlins may occur 

 in poor form between the eastern members of the Finger lakes it 

 may be emphatically stated that the area of close set and well 

 developed drumlins does not reach south on the high ground east 

 of Seneca lake, but that extensions of the drumlin area do reach up 

 on the high ground west of Seneca lake and as far west as to the 



