ESKERS IN THE VICINITY OF ROCHESTER, NEW YORK. 229 



Leverett has mapped two eskers as terminating in this loaf- 

 shaped hill (62, plate III). The second one he indicates as parallel- 

 ing on the west the one figured and described in this paper. Elevated 

 ground occurs beyond the swamp that borders this esker on the west 

 but its breadth and its other characters are not at all like those of 

 eskers. It is half a mile wide, irregular in form, 20 to 60 feet above 

 the swampy ground on the east and extensively dissected by drain- 

 age lines. Everywhere it is under cultivation. Its surface is rolling 

 and not excessively stony, and is largely composed of till. It is 

 undoubtedly to be regarded as morainic, and a northward continua- 

 tion of the Barre moraine. 



Origin. Several features in connection with this esker throw 

 light upon its origin. Its position north of the Barre moraine would 

 seem to suggest that it was forming beneath the ice while the Barre 

 moraine was being built at the ice front. The large blocks of Medina 

 on the surface of the wide portion of the esker near its southern 

 terminus could not have gotten there if the esker was being built in 

 a superglacial stream, and could with difficulty be accovnited for in 

 that position, if the esker was being built in a re-entrance back from 

 the ice front. The influence of the Lockport escarpment on the 

 trend of the northern portion of the esker shows that the esker 

 stream must have been subglacial in this portion of its course at least 

 to have been affected by this feature whose relief was certainly not 

 great enough to extend through the ice and afifect a superglacial 

 stream. The swampy strips on either side of the esker bordered by 

 higher ground farther away indicate the pressure of the ice blocks 

 iminediately adjacent to the subglacial stream on either side. 



Holley esker. Figure 15. This esker is situated between Hol- 

 ley and Clarendon. It originates about a mile southwest of Holley 

 and continues southwestward to within one-half mile of Clarendon. 

 The improved highway that connects the two villages passes along 

 the crest of the esker over the northern part of its course. 



The ridge is over a mile long, it is very broad and near its 

 southern extremity it reaches its greatest height, being 80 feet above 

 the marshy flat ground that borders the whole length of the esker 

 on either side. From the summit of this knoll, "Indian Hill", an 

 excellent view is to be had of the entire surrounding country and par- 

 ticularly over Clarendon and to the southward. 



