﻿GEOLOGY OF THOUSAND ISLANDS REGION 155 



Northward toward Theresa are several extensive sand tracts 

 which are not covered by our maps. East of Strough is a level 

 sand area of 2 or 3 square miles, traversed by the Clayton branch 

 of the New York Central Railroad, which seems to have been mostly 

 leveled by Gilbert waters, but which retains some kame topography 

 along the railroad. Another tract is at Theresa Junction and 

 eastward on both sides of Indian river, and up the river on the 

 west side. Other areas occur : one 2 miles south of Strough, and 

 one a mile south of Theresa. Other tracts, or extension of those 

 noted above, may occur out of sight from the roads. 



On plate 46 a series of sand areas are shown extending from 

 St Lawrence northeast toward Clayton, which are related to the 

 Prospect Park boulder kames. Other small sand tracts are marked 

 on this map, and also on plate 47. 



Some of these sand areas have not only been modified by the sub- 

 merging waters but have been worked on by the winds. The dune 

 characters in some cases rather obscures the glacial origin. Some 

 tracts are fine, clean sand, with basins or swampy intervals, like 

 the Theresa Junction area. It would appear that these sands were 

 laid in glacial waters over or among stagnant ice blocks ; subse- 

 quently modified by the lowering waters ; and lastly acted on by 

 the winds. 



Eskers. Plates 46 and 47 exhibit several series of kame knolls 

 lying in definite chains in the same direction as the ice movement, 

 some of them blending into true eskers. One stands on the flood 

 plain of Indian river; another close to the. St Lawrence river, 4 

 miles southwest of Alexandria Bay ; and two parallel chains 3 miles 

 northwest of Lafargeville. The mapping somewhat overempha- 

 sizes the directness and regularity of these esker-kames. The 

 line of sand between the Hogsback and Prospect Park, southwest 

 of Clayton, should probably be regarded as eskerlike, while the four 

 Prospect Park boulder kames, and the Hogsback also, are parts of 

 the chain; that is, they are all deposits made under variable con- 

 ditions by a single glacial river. 



True eskers, gravel ridges of fair continuity and uniformity and 

 lying in line with the ice flow direction, are regarded as deposits 

 in the beds of full loaded glacial streams, either subglacial or su- 

 perglacial. *The true kames are the short lived deltas of the streams, 

 at their debouchment. Only the streams or their deposits which 

 lie in the line of the ice movement could survive. As the ice front 

 recedes the kames may bury or mask the less massive upstream or 

 esker ridges. 



