Geology

A CONTEMPORARY GLACIER AND GLACIAL LAKE; THIS IS HOW LAKE HITCHCOCK MAY HAVE APPEARED 16,000 YEARS AGO.

As the ice melted, the waters of Lake Hitchcock expanded up the Connecticut Valley, reaching the Franklin - Hampshire County area about 16,000 years ago. Great amounts of clay settled to the lake bottom, forming sediments known as varves, while streams brought loads of gravel and sand into the lake shore deltas. 
CONTEMPORARY GLACIER WITH A DELTA OF GRAVEL AND SAND EMPTYING INTO A GLACIAL LAKE.
Today, the deltas are mined for their gravel. 
CANOE BROOK SITE ALONG THE CONNECTICUT RIVER IN VERMONT. THIS IS A THICK DEPOSIT OF LAKE HITCHCOCK VARVES
Lake Hitchcock clay deposits (varves) have been mined for brick making and landfill linings. The shoreline and lake bottom areas are prominently marked in the Greenfield area by terraces. The shoreline, just like a bath-tub ring, is preserved in the flat tops of deltas found at an elevation of 250 - 300 feet (above sea level) while the flat lake bottom is found at elevations of about 200 - 250 feet (note: these numbers change as one goes either north or south, due to glacial "rebound" effects). By the time it drained, about 14,000 years ago, with all its sediment layer fill, Lake Hitchcock was only about 50 feet deep. With the lake gone, the Connecticut River came back to its valley and started to erode the Hitchcock sediments. 
It has left abandoned channels (oxbow lakes) in many areas as floodplains were created and where the land was harder to erode, scenic narrow valley segments developed sometimes with waterfalls and rapids, great places for rock hunting, boating, and fishing. 

infos taken from  www.umass.edu