No. 6.] UPHAM — GEOLOGY OF NEW HAMPSHIRE. 331 



extend long distances, but have heretofore escaped notice, owing 

 to the large amount of levelly stratified drift, forming the con- 

 spicuous terraces and plains by which the underlying kames are 

 often nearly concealed. 



The origin of the kames has been a question much discussed 

 by European geologists, and the theory commonly accepted on 

 both sides of the Atlantic was, that they were heaped up in these 

 peculiar ridges and mounds through the agency of marine cur- 

 rents during a submergence of the land. Even if such ridges 

 could be formed by this cause, under any circumstances, it seemed 

 impossible to account thus for the kames in the Connecticut and 

 Merrimack valleys, which, being bordered on both sides by high 

 hills, would have been long estuaries, opened to the sea only at 

 their mouths, and therefore not affected by oceanic currents. 

 From the position of these peculiar accumulations of gravel, which 

 are overlain by the horizontally stratified drift, the date of their 

 formation is known to be between the period when the ice-sheet 

 moved over the land aud that closely following, in which this 

 more recent stratified drift was deposited in the open valley from 

 the floods that were supplied by the melting ice. We are thus 

 Jed to an explanation of the kames, which seems to be supported 

 by all the facts observed in New Hampshire, and which appears 

 to apply, also, to the similar deposits which have been described 

 in other parts of the Uuited States and in Europe. During the 

 melting of the ice-sheet, it became moulded upon the surface, by 

 this process of destruction, into great basins and valleys ; and at 

 the last, the avenues by which its melting waters escaped came 

 gradually to coincide with the depressions of the land. As the 

 melted area slowly extended into the continental glacier, its vast 

 floods found their outlet at the head of the advancing valley. 

 This often took place by a single channel, bordered by ice walls, 

 as was the case along the whole Connecticut kame ; but in the 

 Merrimack valley, and in eastern New Hampshire and Massa. 

 chusetts, these glacial rivers also frequently had their mouth by 

 numerous channels, which were separated by ridges of ice. In 

 these channels were deposited materials gathered by the streams 

 from the melting glacier. By the low water of winter layers of 

 sand would be formed, and the strong currents of summer, layers 

 of gravel, often very coarse, which would be very irregularly 

 bedded, here sand, and there gravel accumulating, and without 



Vol. VIII. v No. 9. 



