ANDROSOOGGm LAKES-PORTLAND SYSTEM. 231 



mentaiy clay. The proper interpretation of tliis fact is uncertain. The sea 

 waves may have washed away the top of the gravel ridge and strewn the 

 gravel over marine cla}^ previously deposited on the flanks of the ridge. 

 On the other liaud, the glacial rivers may have laid down both the clay and 

 the overlying coarse sediments in their present positions, either in a broad 

 kame channel approaching the character of a glacial lake or in a bay of the 

 sea inclosed between lateral walls of ice. But in the last-named case the 

 plain ought to show a transition into the marine clays at the south end of 

 the plain. The abruptness of the transition favors the hypothesis that the 

 plain was deposited in a glacial lake, and that some of the marginal clay 

 is not marine but osar border clay. Yet for a mile north of Cumberland 

 Center the ridge is so situated that it would be much exposed to the waves 

 of the sea. Its surface is gently roimded in cross section, and the above- 

 described phenomena may be due to wave action. It will require study of 

 many sections in order to write out the full history of the plain near Cum- 

 Ijerland Center. 



Between Walnut Hill station on the Maine Central Railroad and Cum- 

 berland Junction there are two plains of glacial gravel lying one-fourth 

 mile east of the main ridge or plain. A projecting spur of the main plain 

 has been extensively excavated by the railroad company a short distance 

 south of Walnut Hill station. 



South of Cumberland Center lies a rather level region covered by 

 marine clay, and no gravel appears on the surface for about a mile. About 

 ■one-fourth of a mile west of Cumberland Junction, Maine Central Rail- 

 road, the gravel begins again as a broad ridge, with gently arched cross 

 section, capping- the top of a low north-and-south hill. This ridge extends 

 southward to within one-fourth of a mile of West Falmouth station, it being 

 narrower and somewhat discontinuous toward the south. At various places 

 bars or tongues project obliquely down the eastern slope of the hill. South 

 of West Falmouth lies the plain of marine clay that borders the Presiimp- 

 scot River. No glacial gravel appears in this plain for more than a mile. 

 A short distance south of the river a small gravel plain appears on the top 

 of a low hill. Two other small plains, separated by intervals, bring us to 

 A much larger gravel plain, known as Stevens Plain, situated at Mornills 

 Corner in the town of Deering. This plain is somewhat oblong in shape. 

 It is nearly a mile in length, and about half as broad. It is now very 



