144 SURFACE GEOLOGY. 



feet. The height of Saco river at the state line is about 400 feet above 

 the sea. 



Kavies betivccn Saco River and Six-Mile Pond. 



Along the Portsmouth, Great Falls & Conway Railroad a very remark- 

 able series of kames extends six miles, from near Conway to Madison 

 station. The railroad survey shows that the water-shed here is very low. 

 It is 516 feet above the sea, being only 70 feet above the Saco river at 

 Conway, and only 60 feet above Six-mile pond {also called Silver lake). 

 This low avenue is one half mile to one mile wide, extending nearly from 

 north to south ; it is bordered on both sides by hills from 300 to 500 feet 

 higher, those on the west side rising in almost perpendicular cliffs. The 

 kame begins at Pequawket pond, a mile south-west from Conway Corner 

 and Saco river. A ridge 40 feet high forms the west shore of this pond, 

 and is thence nearly continuous for about three miles southward, lying 

 on the east side of the railroad and Pequawket brook, which drains the 

 part of this low valley that is tributary to the Saco. This kame is nearly 

 straight, and for the most part consists of a steep narrow ridge 40 to 75 

 feet high, being composed of interstratified sand and coarse gravel, with 

 occasional large boulders. A quarter of a mile south-west from Pequaw- 

 ket pond the top of this kame becomes 200 to 300 feet wide, and is level 

 like a terrace. An excavation shows that the stratification here is nearly 

 horizontal in the interior of the deposit, which is sand or fine gravel, but 

 it is abruptly inclined on its west side, conformably with the slope of the 

 kame. Low, swampy areas and occasional small ponds lie on the west 

 side of this kame, and arc interspersed farther to the south among irreg- 

 ular ridges and mounds. These unfilled depressions prove that very lit- 

 tle erosion has been effected by the present streams ; and that these 

 deposits of modified drift owe their form to deposition in the channel of 

 glacial rivers, while the ice remained unmelted on each side. 



The southern part of this series of kames lies principally on the west 

 side of the railroad, covering an area a third of a mile wide, and bounded 

 on the west by the precipitous face of Pine and Hedgehog hills. Along 

 the lowest part of the valley, near the railroad, the ridges consist mainly 

 of gravel with little clear sand, and are much coarser than in the north 

 part of the scries ; but their pebbles are plainly rounded, and of such 



