Cushing — Geolqgy of Clinton County. 



Series VI. There has not been sufficient time at my command t<> 

 bestow on the Pleistocene deposits the attention they deserve. They are 

 widespread throughout the county, often in sufficient force to completely 

 obscure the underlying geology over considerable areas. They w ere, in part, 

 formed by glaciers and the streams to which they gave rise ; in part, in the 

 body of standing w ater w hich occupied the Champlain valley just after the 

 retreat of the ice, and which had, at first, a level much above that of the 

 present lake, when it was probably fresh w ater, while later it was an arm of 

 the sea. 



Glacial deposit*. Away from the lake, the county is covered with a 

 heavy deposit of till. Over the high plain it is widely extended and largely 

 masks the irregularity of its pre-glacial surface. In the hilly tract it is mainly 

 confined to the valleys, though often prominent on the gentle northern slopes 

 of the ridges. Sections show it to be mostly very stony and very sandy, as 

 might be expected from the wide expanse of Potsdam country over which the 

 ice moved. 



Moraines have been noted at various points, but any attempt at mapping 

 them would be premature. Much of the surface of the high plain is insuf- 

 ficiently drained, abounding in swamps, some of very large extent. Rough, 

 jagged boulders, mainly of Potsdam sandstone, are widespread over the 

 surface, often forming veritable trains, and being exceedingly numerous. 

 Some of these Potsdam boulder trains extend well into the gneiss country. 



Glacial striae have been observed at many points. They are commonly 

 well preserved on the palaeozoic rocks, but none have been noted on the older 

 rocks, although these are often well polished and smoothed. Along the lake 

 their direction is approximately that of its trend, those observed varying from 

 S. 15° E. to S. 15° W. and those on the high plain have the same general 

 direction. As the hills are neared and entered, how ever, the general direction 

 is to the southwest, corresponding to the general trend of the ridges and 

 valleys. 



A magnificent, long, esker-like ridge, which well merits description,* 

 occurs in the county. It is found in the low strip, only two or three miles 

 back from the lake, and forms a topographic feature of sufficient prominence 

 to be clearly brought out by the twenty-foot contours of the new maps. First 

 recognizable in Beekniantown township about two miles smith of Ingraham 

 post office, it runs north in a curve to that point, then bears to the w est 

 of north through Chazy. In the central part of that tow nship its course is 



*Mr. S. P. Baldwin has uoted the presence of this ridge. American Geologist, March, 18U4, p. 177. 



