NORRIDGEWOCK-BELGRADE SYSTEM. 181 



sand and clay to the base of the high hills. It does not seem possible 

 the kame border plain could end so abruptly as it does on the west at 

 the swamp above mentioned, unless at the time of deposition, of the border 

 clay as well as of the alluvium of the Carrabassett Valley at this point, 

 the area where the swamp now is was then covered b}^ ice. It is possible 

 that the border clay itself happened to be just high enough to prevent the 

 water of the Carrabassett from passing westward, though that condition 

 would be extraordinary. 



Apparently the glacial history of the region along this gravel series 

 is as follows: A small glacial stream deposited the gravels in rather narrow 

 channels within the ice. By degrees this channel became widened to 

 several times its original breadth, and in this broad channel was deposited 

 the osar border clay. Then the ice on the east side of the border clay 

 melted and the border plain was submerged in the great sheet of (estu- 

 arine?) water wliich then filled the valley of the Carrabassett to a breadth 

 of several miles. But the ice on the west side of the osar channel, where 

 the swamp now is, probably still lingered for a time and prevented the 

 deposition of fine sediments over that part of the valley. The swamp 

 would naturally be covered by a pond previous to the cutting of the 

 ravine of erosion to the Carrabassett by the small brook, its outlet. 



Some of the short deposits of gravel at the north end of the series may 

 be small delta-plains, and mark stages in the extension of the broad glacial 

 channel northward. A possible connection of the Anson-Madison series is 

 found in Embden. A kame about three-fourths of a mile wide is found 

 between Fahi and Sands ponds, in Embden, and another near Hancock 

 Pond. I did not explore the region about Embden Great Pond, and do not 

 know whether there is a continuous series of gravels between the two noted. 

 It is quite possible this is a branch of a Kennebec Valley glacial river. 



Length of the Anson-Madison series, about 10 miles. 



NORRIDGEWOCK-BELGRADE SYSTEM. 



Provisionally these gravels are classified as a distinct system, though a 

 sufficiently careful search beneath the sedimentary sand and clay of the 

 Kennebec Valley may yet show that they are a continuation of the Anson- 

 Madison system, and that both are connected with the gravels of the upper 

 Kennebec Valley. 



