GLACIAL AND POST-GLACIAL HISTORY 469 



Erosion of tributaries flowing into southern Lake Champlain. — 

 From South Bay northward the tributaries from the west have cut 

 valleys 40-60 feet deep below the top of the clay, and in a few cases 

 near the lake shore as much as 60-80 feet deep. Between the valleys 

 the points of land show cliffs furnishing numerous exposures along 

 the Delaware and Hudson R. R. The streams on the east side of 

 the lake are less numerous and flow down from land with a less 

 elevation ; in general, their valleys are not so extensive. Several show 

 erosion to a depth of 40-60 feet, and perhaps one has cut as deep as 

 100 feet near its mouth. These figures refer to the depth of the valley 

 above Lake Champlain level, and do not include depths below the 

 lake-level. The lower parts of many of these tributary valleys are 

 drowned for a distance of three-tenths of a mile from the chfl heads, 

 and swampy bottoms farther up the valley in some cases occupy a 

 probable former extension of the lake for five-tenths to seven-tenths of 

 a mile. 



Charles Emerson Peet. 



Lewis Institute, 

 Chicago, 111. 



^To he concluded.^ 



