NOREIDGEWOGK-BELGRADE SYSTEM. 183 



of Messalonskee Pond for several miles toward Oakland. If the sea stood 

 at the level of this delta-plain, it would at that time have tilled the valley 

 of Messalonskee Pond, and a deep sheet of salt water -4 miles or more wide 

 would have extended northward from the noi'thwestern part of Augusta 

 through Belgrade, Sidney, Oakland, and Waterville, and such a body of 

 water must have deposited abundant sediments. The sudden disappearance 

 of the clay a short distance east of the osar-ridges north of Belgrade station 

 is inconsistent with the hypothesis that the delta above mentioned was 

 deposited in the open sea. On the contrary, these facts strongly favor the 

 theory that the delta-plains which appear at intervals in the course of the 

 system from the south part of Norridgewock to Belgrade station were 

 deposited in g-lacial lakes, and that the bordering plain of sedimentary 

 clay is osar border clay, laid down in a very broad channel within the ice, 

 or perhaps partly bordered by the hills. 



South of this point the gravel takes the form of a continuous ridge for 

 several miles, being cut through by the Maine Central Railroad at Belgrade 

 station. Just south of the station the ridge is strewn with many good-sized 

 bowlders having till shapes. In the southeastern part of Belgrade the 

 system expands into a broad series of reticulated ridges inclosing numerous 

 kettleholes and basins containing twenty lakelets, most of them without 

 visible outlets. On the west of these plains the ridges have steep side 

 slopes, and are simply windrows of coarse gravel, cobbles, bowlderets, and 

 bowlders, all very well rounded. Going south and east we find the ridges 

 becoming lower and broader and the matter contained in them finer, and 

 they presently blend into a rather level plain of fine gravel and sand in 

 the northwestern part of Augusta, and this soon passes by degrees into 

 marine clay at an elevation of near 250 feet or more. 



A short ridge in Manchester is the only glacial gravel found south of 

 this system, and that is probably not connected with this. This series dates 

 from the last pai"t of the Glacial period, when the ice had retreated so far 

 northward that the glacial river flowed into the sea in the northwest part of 

 Augusta. South of where this glacial river flowed into the sea the clay is 

 very deep. A stream has eroded it to a dei^th of 80 feet, and yet apparently 

 has not cut to the bottom. There is an old sea beach on the hill lying just 

 west of Augusta, being especially well developed on the southern brow of 

 the hill near the top. Otherwise I have not been able to find any very 



