COEINNA-DIXMOjSfT SYSTEM. 141 



west past Plymouth Village and empties into the Sebasticook River a few 

 miles below Newport Village. In Dixmont the valley of this stream is 

 very level and a half mile or more broad. A continuous plain of clay and 

 silty clay overlying fine sand (the reverse order of the ordinary valley 

 alluvium) is found in this valley all the way from Troy, through Dixmont 

 and Plymouth and thence along the Sebasticook and Kennebec valleys, to 

 the sea. This clay is proved by its fossils to be marine as far east as Pitts- 

 field, and perhaps as far as Newport. I have often suspected that a narrow 

 arm of the sea connected the Kennebec and Penobscot bays of that time, 

 along the low ground where Etna Bog is. Now the gravel-and-sand plain 

 which seems to terminate the Corinna-Dixmont system has the general 

 character of a delta deposited where rapid streams flowed into a body of 

 still water and are rapidly checked. At once our attention is called to the 

 large plain of fine sediment in the valley of Martin Stream, in which this 

 delta lies. This stream is only a small brook, and ordinarily streams of 

 that size would deposit only a very little alluvium. Evidently, at the time 

 this delta-plain 2 miles southwest of Noi'th Dixmont was being formed the 

 valley of Martin Stream in Dixmont and Troy was in large part bare of 

 ice, and was either occupied by a lake contained between the ice on the 

 north and the hills over which the ice had melted at the south, or was filled 

 by an arm of the sea. But the Kennebec Bay of that period could reach 

 this place only along the valley of Martin Stream through Plymouth, and 

 if the sea extended from that direction the delta would have been formed 

 in the valley of Martin Stream at Plymouth Village instead of several 

 miles south of that place. It is evident that when the delta southwest of 

 North Dixmont was being deposited, the ice must still have remained at 

 Plymouth Village, and this would prevent any communication with the sea 

 in the Kennebec Valley. Was there an arm of the sea in the valley of 

 Martin Stream which connected with the Penobscot Bay? I have traced 

 the marine clay from the Penobscot River as far west as Etna Pond, but 

 between that point and Plymouth is an area not explored. According to 

 Col. A. W. Wilder, quoted in Wells's Water Power of Maine,^ the elevation 

 of Plymouth Bog is 256 feet, and that of Plymouth Village 275 feet. As 

 elsewhere suggested, the sea may have stood at a higher elevation in the 

 interior than on the coast, but in the absence of direct proof to that effect, 



' The Water Power of Maine_, by Walter Wells, p. 89, Augusta, 1869. 



