DRUMLINS OF CENTRAL WESTERN NEW YORK 395 



moldings of the drift, and on the other hand are represented by 

 scoured or rounded roche-moutonneed rock hills (rocdrumlins), it 

 is probable that this class of phenomena will be found somewhat more 

 widely distributed in the glacial areas than has been supposed. 

 However, the requisite conditions for production of typical drum- 

 lins do not seem to have been commonly fulfilled, as vast areas 

 of the glaciated territory seem never to have been subjected to the 

 drumlinizing movement of the ground-contact ice. 



The land surface included in the great drumlin area of New. York 

 is a belt about 35 miles wide, bordering the south side of Lake 

 Ontario, and about 140 miles long (from Niagara river to Syracuse), 

 with a total area of about 5000 square miles. At least half of this 

 area, or 2500 square miles, carries numerous and well developed 

 drumlins. The eastward extension of the drumlin area swings 

 around the east end of Lake Ontario as a belt 5 to 10 miles wide, 

 reaching past Watertown into the St Lawrence valley. An area in 

 Chautauqua county can not be estimated as the region is not topo- 

 graphically mapped, but the drumlins are scattering. 



The New York drumlin area probably includes not less than 

 10,000 drumlin crests, of which on a conservative estimate at least 

 6000 are indicated on the topographic sheets. In the districts where 

 the drumlins are close set from 20 to 35 can be counted in a square 

 of 4 square miles. Five drumlins to the square mile is common. 

 Three to the mile can not be more than the average, counting large 

 and small, and on the 2500 square miles of well developed drumlin 

 topography this would give 7500 drumlins. Estimates have been 

 made by counting the separate drumlin summits or crests indicated 

 by the contour lines in certain limited districts and using the figures 

 for larger areas, with a result giving about 5000 crests for the 15 

 topographic sheets that cover the best parts of the drumlin area. On 

 the 216 square miles of the Palmyra quadrangle [pi. 4] the estimated 

 number of drumlin crests was 800, while an actual count gave 955. 

 Hundreds of minor ridges are beneath the recognition of the con- 

 tour lines. 



The area of well developed drumlins extends eastward around the 

 east end of Lake t Ontario, where they are specially interesting on 

 account of their attitude and peculiar form [pi. 5], and reaches 

 westward as far as the meridian of Batavia. The Pulaski, Sacketts 

 Harbor and Watertown sheets show the northeastward ending of 



