136 GLACIAL GEAVELS OF MAINE. 



A series of ridges separated by intervals of various lengths up to IJ 

 miles begins in the south part of Stetson near the top of a rather low east- 

 and-west liill. The series passes around the west and south sides of Etna 

 Pond and then southeastward. It passes a few rods south of Carmel station 

 of the Maine Central Railroad, and within 2 miles turns rather abruptly 

 southward along the main tributary of the Soudabscook River. In this 

 part of its course it is nearly continuous. For several miles in the northern 

 part of Newburg it takes the form of an osar-plain, i. e., a level plain of 

 well-rounded gravel filling the bottom of the valley, being bordered on each 

 side by a sheet of sedimentary clay which extends back to the hills. The 

 clay-and-gravel deposits have substantially the same upper level or surface. 

 The osar does not follow the axis of the valley exactly, but is often nearer 

 to one side. In the central part of Newburg the gravels leave the valley 

 of the Soudabscook and go south up and over a hill fully 150 feet high. 

 Above this point the valley of this stream contains only a scanty valley 

 drift reaching scarcely 5 feet above the stream, a great contrast to the broad 

 and deep sheets of gravel and clay which fill the part of the valley where 

 the osar river flowed. This clay bordering the central gravel plain is a 

 good example of what I have named the osar border clay. The gravel 

 itself was deposited in a rather broad channel in the ice. This channel sub- 

 sequently broadened so as to extend across the whole valley and the clay 

 was deposited at the flanks of the older gravel plain. A lake 150 feet deep 

 would naturally gather here on the north side of the hill, but it was 

 inclosed by ice walls on the sides (at least most of the time of its existence), 

 otherwise it would have extended up the valley for some miles and the 

 upper part of the valley would be covered by lacustrine sediments. 



On the hill above referred to the gravel is much interrupted. At the 

 southern base of the hill it spreads out into a broad deposit nearly one-half 

 mile across. This is in the valley of another branch of the Soiidabscook, 

 which flows northeastward, past South Newburg, into Stetsons Pond at 

 West Hampden. The gravels take an unusual form. There are several 

 gently sloping terraces, rising one above the other, each separated from the 

 adjoining ones by rather steep bluffs which are nearly parallel witli the 

 strike of the hillside. The higher terraces on the north are narrower and 

 composed of coarser material than those on the south. The deposit as a 



