MAP DETAIL from
"Map Showing the Thickness and Character of Quaternary Sediments in the Glaciated United States East of the Rocky Mountains"
U.S. Geological Survey Miscellaneous Investigations Series Map I-1970
1993-1998
by David R. Soller
These images show Lake Champlain and portions of New York (near Plattsburg) and Vermont (near Milton). In the western half of the Lake, a deep channel is shown. This channel was carved by the glaciers and was filled with fine-grained sediment when the ice retreated to the north and dammed the Champlain valley. At that time, to the south of present-day Milton, a large amount of sand and gravel (shown on the map detail in yellow) from the melting ice entered the Lake, depositing as a delta above the fine-grained lake sediment. The blue dots within the yellow area indicate the presence of fine-grained sediment beneath the sand and gravel of the delta. To the west and east, in the northern Adirondacks and Green Mountains, bedrock is sparsely covered by glacial till (green and tan striped pattern on the map).
