192 GLACIAL GRAVELS OF MAINE. 



clay is so abrupt as to indicate that the glacial waters were quite suddenly 

 checked after entering the salt water. This delta is situated near the south- 

 east angle of Sabatis Pond. Groing south we find no glacial gravel rising 

 above the marine clays for somewhat more than 2 miles. Then a low plain 

 about half a mile long is found on the west side of Sabatis Stream, and 

 then there is another gap of half a mile. A nearly continuous, low, broad 

 ridge then begins and extends southward to Lisbon station of the Maine 

 Central Railroad. Just north of the station it expands into a broad ridge 

 or mound called Whites Hill, which rises fully 100 feet above the clay 

 covering its base. Wells show this clay to be more than 40 feet deep. 

 From this place southeastward to Lisbon Falls extends what is known as 

 Lisbon Plain. It is a rather level plain of horizontally stratified sand and 

 clay, while here and there low ridges of glacial gravel rise above the finer 

 sediments which overlie it. This plain lies in the angle between Sabatis 

 Stream and the Androscoggin River, and at the time the sea was expanded 

 would be subject to the action of the tidal currents of both the valleys. 

 On general grounds this plain might be considered a marine delta, brought 

 down from the north by the glacial river we have been tracing, but its prox- 

 imity to the Androscoggin makes it certain that it is in part an Androscog- 

 gin River delta. East of Lisbon Falls this gravel series consists of four 

 broad ridges or plains, all situated on the north bank of the Andi-oscoggin 

 River. The first is situated about one-fourth of a mile east of Lisbon 

 Falls. The second is about 1^ miles east of this, and consists of two large 

 and broad ridges, inclosing a deep kettlehole. The kame stuff is here very 

 coarse, containing great numbers of very round cobbles, bowlderets, and 

 bowlders. This deposit is half a mile long from east to west, and about 

 half as broad, and rises 100 feet above the Androscoggin River. About 1^ 

 miles farther east is another mass of glacial gravel of about the same size 

 as the last named, but rather level on the top and containing few large 

 stones. At the river bank it forms a steep bluff 100 feet high. After 

 another interval of aboiit 1^ miles a fourth plain of sand, gravel, and cob- 

 bles is found as a terrace rising only 30 or 40 feet above the Andi-oscoggin 

 River. It is not more than one-fourth of a mile long and less than half as 

 broad. Its situation near the river and its level top make it resemble val- 

 ley drift, from which it can readily be distinguished by a comparison with 

 the drift of the river above and below this point. The stones of this gravel 



