144 SURFACE GEOLOGY. 
feet. The height of Saco river at the state line is about 400 feet above 
the sea. 
Kames between Saco River and Six-Mile Pond. 
Along the Portsmouth, Great F alls & 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 4o 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 are 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 series; but their pebbles are plainly rounded, and of such 
