GLACIAL AND POST-GLACIAL HISTORY 457 



EASTERN PASSAGE FROM HUDSON TO CHAMPLAIN VALLEY. 



East of the highland through which is the Lake George passage 

 the lowland of the Hudson valley is continued to Lake Champlain 

 with a width of 5-6^ miles. The higher hilltops in this lowland are 

 300-400 feet below the highland farther east, and are more than 

 double this amount below the western highland. The lower hills 

 in the lowland have elevations of 200-400 feet lower than the higher 

 and reach elevations of 300-520 feet. 



The clay and stratified drift found in the Hudson Valley is hke- 

 wise found through this lowland connecting the Hudson and Cham- 

 plain Valleys. South of the Addison-Rutland county line and east 

 of Lake Champlain it is somewhat discontinuous because of the 

 numerous hills rising above the levels reached by the waters in which 

 the clay accumulated. In the lower lands along the narrow part of 

 Southern Champlain it probably was once continuous. Cut into 

 this old clay-floor there is a valley which extends from the Hudson 

 northward. It has two divisions which will be called the Fort 

 Edward Valley and the Whitehall-Putnam Station Valley. These 

 will be described presently. (See Fig. 18, Nos. 94, 99, 103.) 



CHAMPLAIN VALLEY. 



The lowland of the eastern passage above described extends into 

 the Lake Champlain region, where it is found between the Adiron- 

 dacks on the west and the Green Mountains on the east. It is made 

 of the softer sedimentary rocks generally, over which are the clays 

 and other classes of drift corresponding to those found in the Hudson 

 Valley. 



EAST SIDE OF LAKE CHAMPLAIN. 



North of the Rutland county Hne the more hilly higher land 

 recedes eastward from the lake shore, and from the descriptions of 

 Baldwin^ and some observations of the writer it would seem correct 

 to state that the lower land near the lake is marked by a wide clay- 

 mantled plain as far north as the Winooski, where gravel and sand 

 deposits interrupt. It occurs again north of the gravel and sand 

 plains of the Missisquoi River. To the eastward the clay decreases 

 in quantity or ceases altogether, and on the higher land the drift- 

 covered or bare rock hills cease to be mantled with the clay. 



1- American Geologist, Vol. XIII (1894), pp. 170-84. 



