No. 6.] UPHAM — GEOLOGY OF NEW HAMPSHIRE. 333 



Soucook river and the west side of Merrimack river, to Man- 

 chester, a distance of twenty miles. Their height varies from 

 60 to 125 feet above the river, and they are often nearly covered 

 by the alluvium. Those ridges are coarser than the kame of 

 Connecticut valley, consisting almost wholly of very coarse water- 

 worn gravel, with the largest rocks three to four feet in diameter, 

 and containing fewer and only thin layers of sand. 



Another interesting series of kames extends from Saco river to 

 Six mile pond, and from Ossipee lake, south-easterly, along Pine 

 river, and by Pine River and Balch ponds into Maine. The first 

 description of any of these ridges in America appears to have 

 been given by Dr. Edward Hitchcock, in 1842, respecting a 

 series which is well shown in Lawrence and Andover, Massa- 

 chusetts. This series was at first supposed to be about one and 

 a half miles in length ; but Rev. George F. Wright has recently 

 traced it more than twenty-five miles. 



About Dover, and southward, near the sea coast, thick deposits 

 of gravel and sand, sometimes forming extensive plains, are 

 found occupying areas of watershed from one hundred to two 

 hundred feet above the streams, which often flow in wide valleys 

 that are nearly destitute of modified drift. The absence in the 

 valleys of the terraces which mark erosion through modified 

 drift, shows that they were never filled with the same materials, 

 and that these remarkable plains and ridges were deposited in 

 their present isolated position, with wide areas of lower land at 

 each side. How this took place we can only explain by referring 

 the formation of these deposits to the same causes which pro- 

 duced the kames. The ice-sheet still remained unmelted upon 

 each side at the time of their deposition, filling the valleys and 

 wide areas of low land, over which this gravel and sand must 

 otherwise have been spread by the current of the floods on which 

 they were brought. The most extensive of these plains occur about 

 Willand and Barbadoes ponds, near Dover, and in Newington 

 and the north-west part of Portsmouth. Broadly rounded 

 deposits of the same class form the elevations on which the villages 

 of Rye, North Hampton, and Hampton are built. A very inter- 

 esting ridge of this kind extends from north-west to south-east 

 through the city of Newbury port, Massachusetts. 



The extensive level plains and high terraces which border the 

 rivers of New Hampshire, constituting the most conspicuous and 

 by far the largest portion of our modified drift, were also deposited 



