MOOSEHEAD LAKE OSAR. 129 



appai-ent gap in the gravels of somewhat more than a mile. In Charleston, 

 not far north of the Corinth line, a ridge rises above the clay. It is low 

 and has gentle side slopes.. It extends southeastward for several miles, 

 passing about one-half mile west of East Corinth, here becoming higher 

 and narrower and with steeper sides. Near hei'e many boiling springs 

 issue from the base of the ridge. The ridge is bordered on each side and 

 partly covered to a height of 10 or more feet by sedimentary clay. The 

 gravel is readily permeated by the rains, but the water can not readily 

 escape from the sides of the ridge on account of the rather imperviotis 

 clay. In this natural channel it runs lengthwise of the ridge. Coming to 

 the lower grounds, it fills up the gravel to the top of the clay and boils 

 over the top or escapes through the clay near the gravel. In the lowlands 

 wells dug in the gravel ridge reach water, but the uplands are so dry that 

 the winds circulate freely through the gravel and cobbles. The cellars of 

 houses built on the gravel in such situations are exposed to rapid currents 

 of air in time of high winds, and have to be cemented tight before the 

 houses are habitable. In various parts of the State great numbers of wells 

 have been dug in the glacial gravels in such situations that it was inevitable 

 that all the surface water would be at once conducted away to lower levels, 

 and where it would be impossible to get water without penetrating the 

 gravel into the underlying till, and the loose gravel generally caved in 

 before this depth could be reached. 



In Corinth the osar and the neighboring clay are in a few places 

 sprinkled with bowlders having till shapes, probably dropped by ice floes. 

 The ridge is for several miles parallel with the Kenduskeag River. Near 

 the south line of Corinth the osar crosses the Kenduskeag as a shallow 

 bar extending across the stream. The water plunging over the bar has 

 eroded a deep hole directly below it, known as the "Salmon hole." In 

 general, if the explorer of glacial gravel hears of a salmon hole on an 

 east-and-west stream, he may at once suspect it is formed where a stream 

 flows over a submerged osar. The osar now turns southwesterly and soon 

 disappears on the surface, yet c,an be readily traced for about a mile beneath 

 the marine clay. By inquiries concerning the nature of the soil found in 

 digging wells, it is often possible to trace an osar which is deeply hidden 

 beneath the clay, or perhaps may show as a low mound covered by clay. 

 As a typical instance, and in order to fully explain the methods employed 

 HON xxxiv 9 



