SYSTEMS OF GLACIAL GEAVELS. 139 



have been deposited in a glacial lake or in a broad channel inclosed between 

 ice walls and opening into the sea. South of the delta-plains the lenticular 

 mounds grow smaller, and the last known deposit of the series is only a 

 small hummock, which was once wholly covered by marine clay and laid 

 bare by excavations. 



The system is about 15 miles long. 



LOCAL ESKBRS IN DEXTER. 



About 2 miles east of Dexter on the road to Garland are two small 

 ridges or hillside eskers. They begin on the south side of a long sloping 

 hill, not far above its base, and extend out into the rather level valley a 

 short distance. They enlarge somewhat at their south ends, but not into a 

 well -developed delta, such as ends in sand and finally clay. These ridges 

 are less than one-fourth of a mile in length. 



A short ridge of glacial gravel is found near the railroad station in 

 Dexter Village. The valley of Dexter Stream is covered by very abun- 

 dant alluvium of uncertain origin. It is more abundant than usual in 

 a valley of this size. It is possible some of this rather fine sediment is 

 an osar-plain connecting with the system next to be described. I have 

 not explored the valley north of Dexter Village, but have recently heard of 

 bogs without visible outlets being found not far north of Dexter. If this 

 is so, there probably is a system of glacial gravels along this stream, and 

 the fine silt and clay in the valley below Dexter may be frontal matter 

 derived from this stream at a time when the ice had retreated to some point 

 near or north of Dexter. This interpretation would well accord with 

 the finding of the hillside eskers east of the village. 



CORINNA-DIXMONT SYSTEM. 



As above noted, this system may extend to Dexter or farther north, but 

 I was not able to determine the limit with certainty. A well-defined series 

 of glacial gravels is found in the valley of Alder Stream for 3 miles north of 

 Corinna, and thence southward to the junction of this stream with Dexter 

 Stream. The gravel takes the form of level plains in several places, and 

 there are a number of gaps. Its course crosses Newport Pond. It appears 

 as an osar ridge on the south side of this pond, and takes a quite straight 

 general course southward past East Newport station, on the Maine Central 



