280 



deposited in a cluinnel having a bottom as well as walls of ice. 

 When the bonhu'ing ice melted away, it allowed the sand and 

 gravel to fKH down on either side of a ridge of ice ; and the 

 subsequent melting of this core or nucleus of ice caused the 

 crest of the ridsfe to fall in, dividino^ the sinijle ridsfc into two. 

 with kettles between. In the same direct line with the Accord 

 Pond and Gushing Street eskers is the splendid series on the 

 west side of Weymouth Back River, in Weymouth ; and it is 

 in the highest degi'ce probable that they were formed in 

 succession by the same great glacial river. 



Between Union Street and Leavitt Street there is a trans- 

 verse depression or gap in the water-parting separating Weir 

 River and Bound Brook which does not, apparently, rise above 

 the 80 feet contour-line ; and we may suppose that, when the 

 ice-front had retreated from the high land at this point, the 

 imprisoned waters found an outlet here, and Liberty Lake was 

 drained, the overtiow being now into Bound Brook instead of 

 into North River. The continued recession and embayment of 

 the ice, while the waters discharged at this level, formed the 

 temporary lake in which were deposited the sands and gravels 

 of Glad Tidings Plain, the normal height of which is from 65 

 to 70 feet. This plain has a very perfect development in the 

 vicinity of Glad Tidings Rock, between Free and Pleasant 

 Streets, and also west of Gushing Pond and Plymouth River, 

 between High and Ward Streets, and the Weymouth boundary, 

 and north of High Street, between Hemlock Swamp and 

 French Street, surrounding and partially burying the drumlin 

 of Nutty Hill, and also west of French Street. The little 

 plateau known as Pigeon Plain, south of Hobart Street and 

 southwest of Great Hill, is an isolated but singularly perfect 

 portion of this plain. Liberty Plain does not rise directly from 

 Glad Tidings Plain, but a marked depression separates them at 

 nearly all points. The basins of Fulling Mill and Gushing 

 Ponds are a part of this depression ; but even on the line of 

 Main Street, where there is neither pond nor stream, it is very 



