KATAHDIN SYSTEM. Ill 



that the plains were bordered by ice at the time they were being deposited. 

 Not far west of Deblois the plain ends on the south in sand, which passes, 

 by degrees into clay, and there are several areas of sedimentary clay on 

 the north side of the sand plain, and partly inclosed by it. A minute 

 examination may show that some of them were laid down in glacial lakes. 

 In the absence of direct proof to the contrary, I provisionally assign to them 

 all marine origin. According to my present information, the most prob- 

 able interpretation of the facts is this: The plains southeast of Deblois 

 were deltas deposited within ice walls, i. e., in a broad channel or fiord 

 inclosed by ice at the sides, but open to the ocean in front. Subsequently, 

 when the ice had all melted over the lower part of the Narraguagus Valley, 

 the Katahdin glacial river flowed into the open sea not far from Rocky 

 Pond in T. 22, and at this time were formed the large delta-plains situated 

 west and northwest of Deblois. The situation is further complicated by the 

 fact that the great Seboois-Kingman osar river was at the same time form- 

 ing a marine delta in the Narraguagus Valley north and northeast of Deblois. 



The eastern end of the United States Coast Survey base line is situ- 

 ated just at the top of the bluff which borders the Deblois-Columbia Plains 

 on the south. Toward the east the plain becomes narrower and the mate- 

 rial coarser. Near Epping Corner, in Columbia, the gravel forms a plain 

 near one-half mile wide, rising from 40 to more than 100 feet above the 

 marine clays which border it on the north, east, and south. The plains 

 extending from here northwestward toward Deblois are widely known in 

 all this part of the State as the Epping Plains. Near Epping the plain is 

 rolling and ridged on the top and contains numbers of shallow kettleholes. 

 From it proceed several tongues. On the north three of these tongues pro- 

 ject out one-fourth of a mile or more toward the Pleasant River. The val- 

 ley of this river is here a broad and very level clay plain, and the ridges 

 lising steepl}' 100 feet or more above the plain form a very jDrominent line 

 of bluffs. An examination of the map shows that the Seboois-Kingman 

 and the Katahdin osar rivers together drained near one-fifth of the southern 

 slope of Maine, and that all this vast rush of glacial waters converged at 

 Epping — a sufficient cause for the great plains of Columbia, Deblois, and 

 the Narraguagus Valley. 



A tongue of glacial gravel extends from Epping Church southward on 

 the road to Addison. This soon becomes discontinuous and the gravel 



