Davis.] 
376 
[January 18 
2. The terminal moraines of the great ice-sheets, that have 
attracted so much attention of late years, are essentially marked 
by numerous lakes, for hollows are quite as characteristic of these 
deposits as are hills ; and irregularity, more than any positive 
feature, prevails wherever they are found. 
The hollows are of two kinds : they may be spaces which the 
drift, in its uneven accumulation, failed to fill ; or they may have 
been occupied by masses of ice while the space around was filled in 
by sand and gravel, and afterwards a slow melting of the ice 
left its place empty. When the moraine stands well above the 
drainage level, as in the Backbone of Cape Cod, most of the 
hollows will be dry because water can easily escape under- 
ground ; where a less average height is reached, the numerous 
“ bowls ” or “ kettles ” hold fresh-water ponds. They frequently 
have no overflow outlet. 
There are thousands of these little ponds in the various ter- 
minal moraines that curve across our country, most of which are 
too small to be shown on ordinary maps, for they probably average 
under half a mile in diameter. Before the moraine hills about 
them are cleared of their native forests, or when cultivated fields 
occupy only a portion of their surrounding slopes, they are 
charming features in the landscape ; when the clearing about 
them is completed, they have lost in beauty but gained in 
character, as then the surface boulders scattered over the rolling 
mounds are brought to view. Such a view once seen is not to be 
forgotten : I doubt if any other species of lake is so easily 
recognized as this, and to its distinctness of physiognomy is due 
the value of these lakes and their enclosing hills, as evidence of 
former ice-action. 1 
The moraines and their ponds are found among the hills of 
Cape Cod and northward as far as Plymouth, 2 along Long Island, 3 
and across New Jersey, 4 northern Pennsylvania, 5 where Rogers 
IE. Desor, Paysage Morainique, was among the first to point out this value of their 
occurrence. 
2 W. Upham, The formation of Cape Cod, Amer. Nat. 1879. E. Hitchcock, Geol. 
Mass. 1841, ii, 366; 
3 Mather, Geol. N. Y. 1st. Distr. 1843, 160. 
4 Cook, Geol. N. J. Report, 1877, Map and p. 11. 
5 A report on this part of the continental moraine is in preparation by Lewis and 
Wright for the Second Geol. Surv. of Penna. 
