ANCIENT WATER LEVELS OF CHAMPLAIN-HUDSON VALLEYS 143 



is to be concluded from them that in this latitude neither large 

 glacial lakes nor the sea rose so high as the surface of the 

 lowest of these deposits. Much more detailed study of the 

 region than I was able to give it in the search for water levels 

 will be required in order to trace out fully the limits and his- 

 tory of the retreating ice mass of the Fort Edward region. 



Fort ,Edward district heloio the glacial terraces. Below the 

 marginal terraces above described as lying about the Fort Edward 

 district, there are several well marked types of glacial deposits 

 and a varied topography indicative of successive stages of develop- 

 ment through deposition and erosion by water action. Not all of 

 these deposits are pertinent to the inquiry concerning water levels. 



From the vicinity of Glens Falls northAvestward to the base 

 of the Glen Lake terrace and thence northward and eastward 



--» 



i<r^50 Feet -^1 



Fig. 19 Dislocated and overthrust clays, just north of Summit station, looking east, 

 showing oyerthrust to the south 



over the gently rolling country between Patten's Mills on the 

 north and Argyle on the east, knobs and hillocks rising above 

 the level of the clays are till covered or strewn over with glacial 

 erratics. Such are the features observed in traveling from 

 Sandy Hill northeastward to Vaughns or Queensbury. These 

 hillocks, mostly outliers of the Lower Silurian limestone, rise 

 from a rather uniform level of 280 to 380 feet to elevations 

 of from 25 to 50 feet above the surrounding surface. Their 

 drift-covered surfaces indicate that the ice mass, which defined 

 the limits and the breadth of the terraces on the north and west 

 of the basin, on melting left its unassorted debris on the region. 

 The clays in the lower places of this surface indicate the sub- 

 sequent covering of the district by standing water. 



As elsewhere observed, the clays in the floor of the trench 

 of Wood creek northeastward of Fort Edward are ice worn. 



