94 GLACIAL GRAVELS OF MAINE. 



continue southward along Pocumpus and Wabos (or Wabosses) lakes, to 

 near the south end of Machias Third Lake. The accounts as to its course 

 from this point south are conflicting. According to some accounts the 

 gravel continues southeastward and imites with the Topsfield system near 

 the head of Old Stream; according to others the gravel is nearly contin- 

 uous down the Machias Valley, part of the way keeping back from the 

 river. On general grounds the latter appears to be the more probable 

 course of this large glacial river, since the great "Mont Eagle plains" and 

 the "Raceground" demand a large and long river as their origin. But 

 whatever doubts attach to the course of this system in the vicinity of 

 Machias Second Lake, there is no doubt that a system of gravels extends 

 from Machias First Lake southward along the west side of the Machias 

 River, expanding into a broad series of plains in T. 30, known to the deer 

 hunters as the "Raceground." The part of these plains near the Air Line 

 road (Calais to Bangor) is very level and is a delta-plain. Sedimentary 

 clays cover the valley of the Machias River all the way from this point to 

 the sea, which makes it probable that the southern portion of the Race- 

 ground is a marine delta. The glacial gravels continue southward over a 

 gently rolling plain and cross the Mopaug River, where they expand into 

 an extensive series of sand and gTavel plains, known as the "Mont Eagle 

 plains." These plains are reported to contain in places kettleholes and 

 ridges, while in general they are quite level on the top. This indicates 

 that in part at least the Mont Eagle plains are a marine delta. In regard 

 to the section extending from this point to the road from Columbia Falls to 

 Jonesboro my information is quite conflicting. The map shows the system 

 as extending past Libby Lake and becoming discontinuous toward the 

 south, ending near Masons Bay, Jonesboro. The plains in Columbia Falls 

 and Jonesboro are in general quite flat on the top, and show much coarser 

 matter on the north and west than farther south and east. This indicates 

 that in part, if not wholly, they are delta-plains, deposited in reentering 

 bays in the ice or in glacial lakes. 



Length from Bancroft to Masons Bay about 85 miles. 



SISLADOBSIS-PLEASANT RIVER SYSTEM. 



All my informants are agreed that a ridge or horseback of gravel 

 extends from Sand Cove at the south end of Sisladobsis Lake nearly south 



