Paleontology and geologyIce sheets advanced and retreated over Massachusetts several times during the Quaternary. Evidence of Pleistocene glaciation includes deposits left behind by Glacial Lake Hitchcock, which formed in the Connecticut River valley. Bedrock polished and scraped by glaciers is easy to find throughout the state; there is a particularly nice exposure along the Holyoke ridge near South Hadley in the central part of the state. Cape Cod bedrock is buried by 200 to 600 feet of glacial till and outwash deposits. Mastodon bones and fossilized molluscs have been recovered from Quaternary sediments on Cape Cod. |