BRIDGTON-BALDWIN SERIES. 245 



matter, bordered on each side by a level plain of sand iip to about one- 

 fourth mile in breadth. It is an instructive instance of the broad osar. At 

 Sandy Creek Village even the central parts of the plain are sandy. The 

 valley followed by the railroad is a remarkably level pass through the high 

 hills of southern Bridgton and the eastern part of Denmark. Near the 

 east line of Hiram and at the north end of Barker Pond the gravels turn 

 abruptly south, while the railroad continues its southwest course to Hiram 

 station. The glacial river here took its coiu-se southward along the sides 

 of Barker and Southeast ponds, and then it flowed up and over a hill 100 

 or more feet high. On the north slope of this hill are several horizontal 

 terraces of sand at various heights above Southeast Pond I found no 

 recently blown sand in the region, and these terraces have the shapes of 

 beaches rather than the rounded outlines of sand dunes. A considerable 

 erosion has been effected by small brooks which here and there have cut 

 through the terraces at right angles. I do not see how the terraces can be 

 due to unequal erosion by streams of a once continuous plain of sand. The 

 place deserves careful study. The brief examination I was able to give it 

 suggested that the terraces were beaches formed at the edge of a body of 

 water the surface of which was gradually falling. I saw no sign of an 

 erosion of the till. More probably a broad, continuous osar-plain of sand 

 was deposited on the hillside, and this could easily be eroded by even small 

 waves, so as to form cliffs of erosion and corresponding beach terraces 

 transverse to the slope of the osar-plain. At several excavations in the 

 terraces bowlders from 2 to 6 feet in diameter were seen in the midst of the 

 sand. They were till bowlders, not the rounded ones of the glacial gravels. 

 Wind might have covered the bowlders with sand, but can not account for 

 their having been di'opped upon previously deposited sand. At the exposures 

 examined the bowlders were surrounded on all sides by well-assorted sand, 

 and there was nothing resembling till upon or within the sand — only a few 

 isolated bowlders, whereas the till contains more small stones than large. 

 If they were dropped from the roof of a subglacial tunnel, the tunnel must 

 have been fully one-fourth of a mile wide, and we must account for the 

 presence of only a few bowlders instead of a sheet of till. The theoretical 

 questions arising in connection with this locality will be discussed more 

 fully later. 



Having crossed the hill south of Southeast Pond, the glacial river next 



