214 ROCHESTER ACADEMY OF SCIENCE. 



depression in the middle segment signifying the weight of an ice arch 

 upon its surface, all point to the subglacial origin of the ridge. Like- 

 wise the kettles that parallel its course are evidence of the weight of 

 ice masses bordering the esker ( 122). One gap in the course of the 

 esker has been due to stream erosion and is now occupied by a vig- 

 orous stream. The other gaps may be due to stream erosion but 

 more probably they represent lack of deposition in the subglacial 

 tunnel. 



Palmyra cskcrs. Figures 7-9, plate XII. Xear Palmyra occur 

 several eskers lying in the valleys between the drumlins. Three of 

 these gravel ridges may be seen in going from Palmyra to Marion, 

 closely paralleling on the west the road that connects the two vil- 

 lages ; the fourth lies one and one-half miles northwest of ]^Iarion. 

 All are of sufficient height to be indicated on the Palmyra topo- 

 graphic quadrangle. In length the ridges are short, each being from 

 one-half to three-fourths of a mile long. Their north-south align- 

 ment would seem to indicate that they represent the activity of a 

 single glacial stream flowing southward in a course parallel to the 

 drumlins and to the direction of ice movement. In figures 7-9, plate 

 XII, the ridges are designated A, B, C and D. A being the one 

 nearest Palmyra, D being the one farthest north, lying northwest of 

 Marion. A distance of about six miles separates the ridge near 

 Palmyra from the one near Marion. 



Ridge A. This esker, or esker segment, is of average height, 

 being about 25 or 30 feet for the greater part of its course. It has 

 a rather broad crest with relatively gentle slopes, which locally are 

 exceedingly stony and elsewhere quite free from stones. Its crest 

 ^supports no knolls, being thrown into a series of gentle grades. Its 

 course is not characterized by meanders Avhich were found to be a 

 pronounced feature in a number of eskers studied that are shorter 

 than this. Near the northern portion of the esker several gaps occur, 

 one of which is traversed by a stream, the largest gap being occupied 

 by a number of low kames. In the course of this esker excavations 

 have been made in one place only. But little was gained in the exam- 

 ination of this excavation. It had not been worked for a long time, 

 and the action of the weather had obscured its features. In the 

 accumulated debris at this point coarser stones appeared to be lack- 

 ing entirely. 



