FORMER COURSES OF THE ANDROSCOGGIN RIVER 241 



In explanation of the existing drainage it may be stated that 

 the modern valley of the Androscoggin below Berlin represents 

 more erosion than could have occurred since the last ice retreat. 

 Undoubtedly this valley was greatly widened, straightened, and 

 deepened by the movement of ice through it, and possibly the 

 Mount Winthrop Divide may have been removed and the present 

 drainage brought about by ice action. But river piracy also offers 

 a simple explanation. 



The stream on the east side of Mount Winthrop Divide had 

 a much steeper grade and thus far greater erosive power. Bethel, 

 17-2" miles east of the divide, has an elevation of 635 feet, and the 

 elevation of West Milan, 23 miles west of the divide, is 1,015 ^^^t. 

 The descent eastward from Mount Winthrop is 57 feet to the 

 mile, while the westward descent is 24 feet to the mile. Allowance 

 for erosion does not materially alter the relations. 



From the divide to the Gulf of Maine by the preglacial course 

 of the lower Androscoggin is 90 miles and from the divide to 

 Long Island Sound by the Upper Ammonoosuc and Connecticut 

 rivers is approximately 300 miles. These facts show that favorable 

 conditions for piracy existed. 



The Androscoggin River wore its valley back through the 

 low Mount Winthrop Divide, captured the Peabody River, be- 

 headed the Dead River at Berlin, wore through the low divide at 

 D, captured several streams from the Mahoosuc Range, finally cap- 

 tured the Mahoosuc River, and thus started the present drainage 

 system. 



. FORMER COURSE OE THE LOWER ANDROSCOGGIN RIVER 



It has been pointed out that the present course of the Andros- 

 coggin, in the lower province, between Bethel and the ocean, is 

 abnormal and is of postglacial origin. 



For the preglacial course two possible routes are to be con- 

 sidered: eastward along the line of the Grand Trunk Railway 

 or southward via the valley of Crooked River. The latter appears 

 to be the more probable route on account of its lower summit and 

 freedom from obstructions. 



