220 ROCHESTER ACADEMY OF SCIENCE. 



manner, but after the esker to the south of it had been buih and un- 

 covered by the melting of the ice. During its formation the portion 

 of the esker to the northeast of it was being formed beneath the ice. 

 The elevation itself and the gentle slope westward from it represent 

 outwash at the time this northern portion of the esker was forming, 

 and the kettle to the south probably represents ice block inclusion, 

 the block remaining while the elevation itself was being formed. 



Esker east of Mendon pond. Figure 11, plate XIV. On the 

 east side of Mendon pond is found the finest esker of the Mendon 

 kame area. In many respects it is the finest example of this type of 

 glacial development that was studied. For a distance of 2^ miles 

 it continues its course through the eastern half of the kame area 

 bordered by kames on either hand. It meanders freely, possesses an 

 uneven hummocky crestline, and on either side at its base occurs a 

 succession of kettles formed by ridges passing ofif from the side of 

 the esker and connecting with the adjacent kames. These kettles 

 may contain water forming small ponds and swamps. In altitude 

 it equals or surpasses the other eskers studied, in places rising 100 

 to 125 feet above its base, with very steep slopes and narrow crest. 



The esker begins on the north in one of the highest elevations in 

 Monroe county. This elevation is well shown on the Rochester 

 topographic sheet lying about 1 mile northeast of Mendon pond, 

 with an altitude of 850 feet above sea level. The accompanying fig- 

 ure exhibits only the higher portion of this eminence from the upper 

 surface of which there is a gentle rolling slope outward in all direc- 

 tions except where the esker joins on the south. 



The surface of this elevation is thickly mantled with water- 

 worn stones of all sizes and apparently the greater part of the whole 

 hill is water lain material. Southward from this elevation the esker 

 pursues its meandering course toward the southwest with hummocky 

 crest and steep lateral slopes. About one mile south the ridge ter- 

 minates in a high knoll bordered by a long deep kettle on the east 

 side. Southwest of this knoll and joined to it occurs another higher 

 knob that forms one of the most conspicuous elevations along the 

 whole esker course. A short distance south of this high elevation 

 the esker turns abruptly toward the west and continues nearly a half 

 mile in that direction. The best view of the esker from the Pitts- 



