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From the air, it's easy to see that the sandy
ridge running down the middle of Rainbow Lake, near
campus, is an "esker," the former bed of a
meltwater river that ran through a tunnel in/under
the great glacier that buried this region under a
mile or more of ice until about 12,500 years ago.
Houses built on such porous material can cause
septic wastes to seep into and pollute lakes.
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for larger view of the picture
The Spring, 2001, Paleo class took a field trip
to the Champlain Valley where we found marine
mollusc shells that were left behind when Lake
Champlain was a fjord-like arm of the Atlantic
Ocean at the close of the last Ice Age. Talk about
environmental change: the lake was first fresh with
meltwater, then salty with seawater, then fresh
again when the Valley rose above sea level about
10,000 years ago.
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