MODIFIED DRIFT IN PISCATAQUA BASIN. l6l 



observed at a greater height than about 150 feet above the sea. On the 

 borders of Great bay and Piscataqua river it seems not to exceed a height 

 of 50 feet. A well near the Boston & Maine Railroad, about a mile west 

 from Dover, passed through 20 feet of this compact, pebbly gray clay, 

 below which was a water-bearing stratum of sand. A neighboring well 

 showed 10 feet of similar gray clay; then 2 inches of clear sand; beyond 

 which this clay continued 16 feet lower, and was underlain by I3 feet of 

 mud, apparently containing sticks and leaves, and lying upon ledge. 



At the county farm, three miles north-west from Dover, and about 

 150 feet above the sea, a well showed 50 feet of this clay; which con- 

 tained sandy layers, but otherwise was obscured in its stratification. 

 Stones were frequently found, the largest of them weighing about 100 

 pounds. Below this was a stratum of gravel and sand, which seemed 

 "like the bed of a stream," and yielded an abundance of water. This 

 deposit lies upon till, which is exposed at forty rods to the north. On 

 the west side of Cochecho river, at a bridge slightly farther distant to 

 the north-west, is a kame that probably marks the mouth of the glacial 

 river by which this marine delta was formed.* 



Barbadoes pond, crossed by the line between Dover and Madbury, is 

 surrounded by an elevated plain of gravel and sand,f about 175 feet above 

 the sea, of the same kame-like origin with that about Willand pond. This 

 plain is bounded by an escarpment 10 to 40 feet high. At its foot on the 

 south-east are springs which supply the west part of the city of Dover. 



Southward we find other extensive deposits of the same origin. On 

 the south side of Bellamy river, for a mile and a half east from Madbury 

 station, is a broad ridge of coarse water-worn gravel and sand of about 

 the same height with the plain at Barbadoes pond, and 50 feet higher 

 than the adjoining land, on any side. One mile south from Sawyer's 

 mills in Dover, and in the same line with the foregoing, is a similar ridge 

 two thirds of a mile long and about 150 feet above the sea. The ridge, 

 about 125 feet in height, between Bellamy and Piscataqua rivers at one 

 to two miles north from Dover point, is shown by wells to be the same 



* A recent journey has brought to our notice an alluvial plain on the west side of the Cochecho, opposite to 

 and lower than this delta. It was probably fluviatile, belonging to a later date when the ocean held a lower level. 

 The rounded delta and the imperceptibly sloping plain show the contrast between deposition in deep and quiet 

 water, as of a lake or arm of the sea, and that which takes place from the shallow floods of rivers. 



t The extent of this deposit, and of others described at the south-east, may be seen on Plate VI, p. 146. 

 VOL. III. 21 



