256 GLACIAL GRAVELS OF MAINE. 



valley the terminal moraine of this supposed glacier would naturally fall ' 

 into the subglacial rivers and be modified by water, thus helping to form 

 an overwash or frontal plain in front of the ice as it receded. 



Above Hiram the part of the valley covered by alluvium broadens 

 into a plain, in Brownfield and Fryeburg, near 10 miles in diameter. The 

 floods of valley drift in time covered the w-hole of this broad area, so that 

 it would present the appearance of a lake. In this was deposited a broad 

 fluvial delta extending from Conway, New Hampshire, east to Lovell and 

 Brownfield. For many miles in this broad sedimentary plain the river 

 winds very circuitously and is bordered by only a single bkiff of erosion — 

 that which forms its banks. This indicates that erosion and deposition are 

 here going on at about the same rate. The alluvial plain narrows as we 

 approach the New Hampshire line, and the drift becomes coarser and con- 

 tains much roimded gravel. The erosion terraces along the Saco River 

 vary from 10 to about 50 feet in height above the river. 



THE GREAT COMPLEX OF NORTHWESTERN YORK AND SOUTHWESTERN 

 OXFORD COUNTIES. 



This is a series of plains closely connected by lateral series so as to 

 cover as with a network the hilly country lying west and southwest of the 

 Saco as far as the valley of the Mousam River. In this complex series it 

 is difficult to distinguish tributary from delta branches. On the west these 

 gravels are connected by three lines of gravel plains with the great kame 

 system described by Mr. Warren Upham in the reports of the New Hamp- 

 shire geological survey as extending from Conway, New Hampshire, south- 

 ward to the valley of the Ossipee Lakes. Two of these plains (in the 

 form of osar-plains about one-fourth of a mile wide) extend from Effing- 

 ham, New Hampshire, into Parsonsfield, Maine, while a tract of reticulated 

 ridges nearly 3 miles wide passes from Wakefield, New Hampshire, into 

 Newfield and Acton, Maine. 



The region between the Saco and the Mousam is diversified by numer- 

 ous ranges of hills. If we start south from the broad hill-encircled plain 

 of Fryeburg, which on a small scale much resembles in form the "parks" of 

 the Rocky Mountains, we almost immediately enter the hilly country. In 

 Porter, Brownfield, Parsonsfield, and Cornish many of the higher hills rise 

 to 800 feet or higher, and the slopes are rather steep. Going southward, 

 we find the valleys becoming broader and the hills lower and with gentler 



