226 GLACIAL GEAYELS OF MAINE. 



At the shore of the pond it forms a bluff rising 8 or 10 feet above the 

 water. At the narrowest place this plain is about one-eighth of a mile 

 wide, and a large amount of water was required in order to form it. If 

 the ice in the basin of the pond was all melted at the time of the deposi- 

 tion of this plain, the whole pond must have stood at least 8 feet above its 

 present level, and a delta ought to spread out in fan shape from the mouth 

 of the inflowing stream. Now from this point to Oxford Village the pond 

 is bordered by a clay plain, and a sedimentary plain nearly filled up the 

 lake, which was flooded with water by the building of the dam at Oxford. 

 But south of here no sand or clay borders the lake, except a little near the 

 mouths of the streams — certainly no such sheet as could be expected if a 

 large river flowed into the pond 2 miles from its outlet and at a time when 

 it stood 8 feet or more above its present level. At this time most of the 

 basin of Thompsons Pond must have been covered by ice. Thus the sedi- 

 mentary plains of Oxford appear in part to have been deposited in broad 

 channels bordered by ice, and give good ground for suspecting that these 

 broad channels practically formed a series of glacial lakes in which a part 

 of these fine sediments were deposited. Subsequently the ice melted, and 

 a body of water, probably marine, filled the whole lower valley of the 

 Little Androscoggin. How far this was fluviatile, estuarine, or marine is 

 somewhat uncertain, and the hypothesis is suggested that these broad sheets 

 were, in part at least, bordered by ice. 



From Oxford Village a broad, low, plain-like valley (known as Rabbit 

 Valley) extends southeastward to Poland Post-Office. About a mile from 

 the Little Andi-oscoggin a ridge bordered by ravines of erosion is found 

 in the midst of the plain of sedimentary clay and sand which here covers 

 the valley. Farther south what appears to be a continuation of this ridge 

 rises higher than the plain of fine sediment, and soon crosses a pond,' 

 which nearly divides it into two separate lakes. Whatever be the char- 

 acter of the erosion ridge farther north, this ridge at the pond is distinctly 

 an osar. Within 2 , or 3 miles the ridge is lost in a rather level plain of 

 sand, gravel, cobbles, and bowlderets, which for several miles is from 

 one-fourth to one-half of a mile in breadth. The unmistakable glacial 

 origin of this osar-plain makes it appear possible, perhaps probable, that 

 the rather horizontally stratified plain of clay and sand which borders the 

 ridge toward Oxford Village was laid down in a broad channel within 



