CHAPTER XVII. 

 THE CHAMPLAIN PERIOD. 



GliACIAT. LAKES EAST OF THE CON^TECTICUT KIVER. 



INTRODUCTION. 



It is very remarkable that while the heavy sand aud gravel deposits 

 of a complex series of glacial rivers and lakes extend over the whole eastern 

 half of the three counties east of the Connecticut River, such deposits are 

 almost wholly wanting on the western side. Amherst, in the middle of the 

 area, is about 80 miles from the sea and the same distance from the Sound, 

 and it has come to be very plain to me that the ice front during the retreat 

 of the inland ice was, over this territory, a. northeast-southwest line; not a 

 straight line, but one projecting south in a loop in the broad Connecticut 

 Valley. The effect of this would ])e that the country to the east would be 

 set free on any given parallel earlier than that on the west, and that in the 

 east the headwaters and gradually nearly the whole of the drainage area 

 of each tributary would be set free before the southward-projecting tongue 

 of ice in the main valley would permit its unobstructed passage to join the 

 waters of the Connecticut; while on the western side the ice melted back 

 up the streams to their heads, leaving their lower portions first and using 

 their channels for the passage of their abundant waters, and thus delivering 

 through them to tlie main valley an abundant supply of "gletchermilch" 

 (the line silt from beneath the glacier), but, except in a few cases where a 

 north-south side valley sloped northward, leaving the valleys open and not 

 clogged by the great accumulations of sand found so commonl}' on the 

 eastern side. 



From this it follows that our history of the stratified deposits which 

 accompanied the melting of the ice must begin at the southeast of the region 

 and proceed ncn-thwesterly, ending in the northwest, and we shall find a 

 gradual change in this direction and a remarkable difference on the two 

 sides of the river. 



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