ESKERS IN THE VICINITY OF ROCHESTER, NEW YORK. 227 



length. Its northern portion is indicated on the Albion topographic 

 quadrangle, the remaining part lying in the territory covered by the 

 Medina quadrangle. The esker is associated with the Barre 

 moraine, its southern end being about 1 mile north of the main east- 

 west ridge of the moraine. The country through this section is 

 rolling. In the midst of this rolling plain, occupying a rather low 

 swampy stretch, the esker pursues its course. Its trend is nearly 

 north and south, although both its northern and southern extrem- 

 ities depart appreciably from this general direction. Its height is 

 nowhere excessive, for the greater part of its course only 15 to 30 

 feet, but its length is notable, being about four miles, with but one 

 or two short gaps in this entire distance. 



Leverett has mapped and described briefly this esker (62), the 

 northern part of the ridge shown in the accompanying figure (Fig. 

 13), he apparently regards as moraine, and has so mapped it (62, 

 plate III). 



On the north the esker sets in as a very broad low ridge, the 

 width of the base being several times the height. Arising from 

 swampy land it continues southwestward for more than a mile, its 

 gentle slopes and broad crest not revealing its true character to the 

 casual observer. In places in this portion of the course the esker 

 may broaden until its base is nearly one-quarter of a mile in width. 

 This part of the esker lies banked against the Niagara escarpment, 

 the trend of which has probably influenced its direction. 



One or two exposures occur here. Very little sand is present, 

 chiefly fine to coarse gravel, Medina sandstone pebbles comprising 

 by far the greater part of the material. 



The surface of the esker everywhere in this northern portion 

 is exceedingly stony, the stones being small, about the coarseness 

 of fine gravel, and mantling the surface everywhere. Notwithstand- 

 ing this feature the esker is under cultivation and its slopes are 

 fairly productive. 



Near the southern terminus of this northern portion a distinct 

 ridge joins it from the northwest. This is probably to be interpreted 

 as a tributary to the main ridge. It is a broad, level-topped, gentle- 

 sided elongation, about 700 to 800 feet in length and terminates 

 northwestward in a broad flat-topped elevation with very gentle 

 slopes. 



