ESKERS IN THE VICINITY OF ROCHESTER, NEW YORK. 225 



quadrangle indicates the character of the general area, the esker 

 itself being too inferior to find expression on the map. This esker 

 has already been described (20). 



It is not a large type of its class, being less than a mile long and 

 rarely reaching a height of 15 feet. The most striking feature 

 observed in its study was its direction, this being not far from east 

 to west, or at nearly right angles to the direction of ice movement in 

 this region. However the striae locally do not indicate such a dis- 

 parity between the direction of the ice movement and the trend of 

 the esker. Apparently at least during the closing stages of the ice 

 invasion the local ice movement was toward the southwest. 



The esker begins on the east in a cultivated field with character- 

 istic rolling morainal topography. The distinctly ridge form is 

 scarcely assumed before it is abruptly terminated and succeeded by 

 swampy ground, and then 500 feet farther north it picks up as 

 abruptly and continues onward curving rather sharply toward the 

 westward. Two short breaks, each but a few feet wide, follow in 

 rapid succession and then its course is continuous, till the north- 

 south highway is reached. West of the highway it is much more 

 discontinuous and segmented (see figure) until finally it blends with 

 the heavy morainal features just beyond the railroad. 



It traverses swampy ground throughout its entire course, east 

 of the road the adjacent swamp being wooded, west of the road 

 it being sufficiently dry to be under cultivation. It is quite possible 

 that the breaks are due to stream erosion, although the sluggishness 

 of the illy-defined drainage lines through the swamp would seem to 

 antagonize that idea. 



Several excavations have been made at various places in the 

 esker, though none are recent. Just east of the road such an excava- 

 •tion occurs and also one about 600 feet west of the road, and near 

 the eastern termination of the ridge three excavations are found 

 which exhibit the materials and structure to best advantage. Here 

 the material is very fine for the most part, although little sand is 

 present, with bedding indistinct. Just east of the north-south road 

 the excavation is old and so thoroughly washed down as to be of 

 little value. However, there is some sand here, and the fact that the 

 excavation was continued below the level of the surrounding sur- 



