MODIFIED DRIFT IN PISCATAQUA EASIN. I57 



"On the contrary, there are several large springs on the borders of the 

 lower plains, which are supplied from the body of sand constituting the 

 plain above, and probably in some instances from the pond itself. On 

 the side next the city the springs are about 41 feet lower than the pond, 

 and are of such size that they supply the water for the Cochecho Aque- 

 duct Co. It is probable that these springs are subterranean outlets for 

 the water of the pond, and undoubtedly these and all the others drain 

 some portions of the sandy plain surrounding the pond. * * 



" How extensive the area is which furnishes water to the pond we have 

 no reliable means of determining, because the water-courses and divides 

 are hidden beneath the surface. It may be stated in a general way that 

 the wells sunk into this plain indicate that the water-table rises towards 

 the north and west, and falls towards the south and east." 



In 1876 a water-pipe was laid from this pond to Dover, for which a 

 ditch was dug 25 feet deep for a quarter of a mile through the bordering 

 plain. This ditch (Fig. 39) showed 

 the plain to consist of interstrati- 

 fied gravel and sand, the former pre- 

 dominating, and containing abundant 



f ,, . r . , Fig. 39.— Section of Plain at Wil- 



pebbles, of all sizes up to a foot and J^^ p^^^ somersworth. 



a half in diameter. The whole ap- Depth, 25 feet. 



pearance is kame-like, but the materials are nearly level in stratification. 

 The layers of sand were from a few inches to two feet in thickness, but 

 were short, not being apparently continuous over large areas. At some 

 points only the coarse gravel was found, with no clear sand. No boulders 

 were seen on the surface or in the excavation. 



This plain about Willand pond is the highest land between Salmon 

 Falls and Cochecho rivers, the descent to which is over uneven areas of 

 ledge or till. The shores of the pond on all sides rise steeply to the level 

 of the plain. Much of this escarpment appears to have resulted from the 

 undermining action of waves. In other portions the gravel and sand were 

 deposited with this slope, which, near the point where water is taken for 

 the city of Dover, continues to a depth of 60 feet below the surface of the 

 pond at ten rods from its shore. At that time the hollow which is now 

 filled by the pond, and the wide valleys to the east and west, appear to 

 have been occupied by portions of the departing ice-sheet. 



