206 ROCHESTER ACADEMY OF SCIENCE. 



is significant that those geologists most famihar with existing ice 

 fields, with Pleistocene phenomena and with the particular type of 

 glacial deposits under discussion here, are in accord in the accept- 

 ance of the subglacial hypothesis for the origin of the vast majority 

 of eskers. Such men as Chamberlin, Salisbury, Russell, Leverett, 

 Davis, Woodworth, Tarr, Fairchild, Stone and others, all agree that 

 the subglacial hypothesis best explains the facts. 



Economic Importance of Eskers. 



The sand and gravel these ridges afford are of economic import- 

 ance and there is scarcely an esker that does not show one or more 

 excavations for these materials. In some cases a large part of the 

 esker has been removed, its materials being utilized for building 

 purposes, road construction, and ballast, manufacture of concrete 

 blocks, filling, etc. From a scientific standpoint this is unfortunate, 

 and yet as a resource their materials should be utilized. 



The ridges themselves may be vised as roads to cross swampy 

 ground, to aiiford suitable grade, and to save to the agriculturist 

 arable land by utilizing that least arable. Such roads are level and 

 dry. 



Their surfaces are unsuited to agriculture, and are in most cases 

 untilled, usually being forested. 



Description of Western New York Eskers. 



General statement. The description of the individual eskers 

 that are readily accessible around Rochester follows. In every case 

 the descriptions are in detail and it is hoped that they will serve as a 

 guide for students and others interested in glacial geology who may 

 visit the eskers in the future. The descriptions are followed in each 

 case by a brief summary of the characteristics which tend to throw 

 light upon the origin of the esker in question. 



A contour map of each esker studied was made and this accom- 

 panies the descriptions. The contour interval was purposely made 

 small, 5 feet, in order to bring out the details of the surface config- 

 uration. The linear scale and direction (magnetic) are indicated on 

 each map. A larger scale was used for the width, approximately 

 twice that of the linear scale. This is the first time that eskers have 



