ESKERS IN THE VICINITY OF ROCHESTER, NEW YORK. 219 



the Mendoii kame area. It is east of the main course of the esker 

 although intimately connected with the esker itself and overlooks 

 both Mendon pond and the small pond to the south, lying between 

 the two. Its surface is composed of sand and fine gravel. Near its 

 summit a partly buried boulder occurs with an edge exposed that will 

 measure 8 feet, and another edge that will measure 6 feet in length. 

 It is not wooded. Southwest from this high mound the esker con- 

 tinues for 1,000 feet with a height of 75 feet or more, and with a 

 hummocky meandering course. It then abruptly broadens into an 

 excellent example of an esker fan, which slopes with uneven surface 

 gradually toward the southeast, south and west, and is covered with 

 small rounded stones and under cultivation. 



There was little information obtained as to the composition of 

 this esker. Its surface is typical of eskers in being mantled with 

 gravel. An old excavation occurs north of the road that crosses the 

 esker nearly a mile from its southern termination, which discloses 

 gravel both coarse and fine and also some sand on its north side. 



The northern portion of this esker is paralleled by another 

 ridge on its south side. This second ridge is of about the same height 

 as the esker itself, with the same degree of slope on the flank facing 

 the esker. This slope is wooded. The opposite side toward the 

 southeast is much more gentle and is under cultivation. This ridge 

 is separated by a narrow swamp from the esker described above. 

 Its northward termination is more abrupt and its northern portion is 

 higher than the esker mapped. Otherwise it possesses the same 

 general features as the one studied in detail. These two ridges are 

 to be interpreted probably as a double or reticulated esker. 



Origin. Little can be said regarding the origin of this esker. 

 Near the top of the excavation mentioned above a large boulder was 

 observed lying partly buried in the sand. It could hardly have gotten 

 into such a position if the esker had been superglacial in origin. The 

 prominent elevation near the south end of the esker was formed 

 at the edge of the ice or more probably in a slight re-entrance, or 

 possibly in an area surrounded by ice at a time when the esker north- 

 ward was being formed beneath the ice and probably after the 

 formation of the greater portion of the esker to the south of it. The 

 eminence near the north end of the esker was formed in a similar 



