SOME NEW JERSEY ESKERS. 
G. E. CULVER. 
The terminal moraine of a great ice-sheet is the dividing lin 
between two classes of drift deposits. On the one side the 
material is sorted and stratified; on the other, the ice side 
there is neither sorting nor stratification. The material is piled 
np in the most miscellaneous manner. Huge boulders and fine 
clay, with material of all the intermediate grades of coarseness 
or fineness rest together upon the same bed. This mixture is 
the work of the ice. The stratified beds are formed by the 
water flowing from the melting ice. The moraine itself is built 
up altogether by the ice; but its structure is somewhat modified 
by water action, so that here and there small areas of roughly 
stratified material are found. 
After an ice-sheet has retreated, if the region vacated by the 
ice be examined, it will be found in most cases to be covered by 
the unstratified drift or till to depths varying from a few inches 
to several hundred feet. This is invariably the case in com¬ 
paratively level regions like southern and central Wisconsin, 
southern Michigan, Minnesota, and Iowa. 
In regions of greater elevation and of low mountains, it is 
common to find another class of deposits as well as the usual till. 
Near the front of the ice, but within the moraine, irregular 
heaps of rudely stratified sand and gravel occur. These some¬ 
times lie singly, sometimes iii groups. Occasionally these groups 
take on a morainic 1 aspect. These hills of gravel have been 
called kames by Prof. Chamberlain in distinction from another 
type of gravel deposits often found in the neighborhood of kames 
to which the term esker is applied by the same authority. The 
esker is a long sinuous ridge of gravel extending sometimes for 
many miles with but slight breaks, and crossing low ridges as 
1 Prof. Salisbury has proposed the term kame-moraine for this group. 
