IQQ GLACIAL GRAVELS OF MAINE. 



three ridges inclosing numerous kettleholes and one or two lake basins. 

 The ridges become broader toward the south and coalesce into a level plain 

 of sand, which ends near the road from Branch Mills to China Village. 

 Witliin a short distance the gravels begin again and continue in a nearly 

 straight line southwestward, ending about one-fourth of a mile south of 

 Weeks Mills, in the southeastern part of China. For several miles the 

 gravels are in the form of a long plain one-fourth mile or less in breadth. 

 Near Weeks Mills the plain consists of one or more ridges of arched cross 

 section, flanked and sometimes covered by fine gravel and sand, and the 

 plain is bordered by sedimentary clay, which extends down the Sheepscot 

 Valley to the coast. 



The structm-e of the plain indicates that a ridge was first formed in a 

 narrow channel within the ice. Subsequently a marine or estuarine delta- 

 plain was deposited in a broad channel open to the sea to the south, but 

 still confined between ice walls at the sides. In some respects this delta- 

 plain resembles the osar-plain in its form and relations to the central ridge, 

 but in this case the original ridge was less modified than is usually the case 

 in the osar-plain, so that the distinction between it and the bordering plain 

 is quite sharply defined. 



This system is remarkable for its large size at tlie extreme north end. 

 This indicates a northward extension of the system, but I have not been able 

 to find any. The country is so deeply covered by the marine clay that large 

 gravel ridges might exist beneath the clay and not attract attention. Sev- 

 eral ridges and mounds, probably of glacial gravel, are found near the east 

 base of Parinenter Hill, and they may be a connection of this system. 



The large size of the bowlders contained in the gravel plains at the 

 north end of this system, together with their topographical relations, suggest 

 that they were formed at the front of a mass of moving ice. Several other 

 facts support the same conclusion: 



1. This glacial river formed a marine delta in the southern part of 

 China, 40 miles or more from tide water, at an elevation of about 200 feet, 

 and there is no proof that it at any time flowed farther south. It must 

 hav6 been pretty late in glacial time when the ice had melted so far north 

 as this. 



2. As before noted, the ice could no longer flow south over the hills 



