Preliminary Bedrock Geologic Map of the Vermont Part of the 7.5 X 15-Minute Mount Ascutney and Springfield Quadrangles, Windsor County, Vermont

Bedrock in the Vermont part of the Mount Ascutney and Springfield quadrangles consists largely of, from west to east, Middle Proterozoic gneisses in the core of the Chester Dome, pre-Silurian metasedimentary, metavolcanic, and meta-igneous rocks as a cover sequence immediately above the dome, Silurian and Devonian metasedimentary and metavolcanic rocks of the Connecticut Valley sequence, and Ordovician to Silurian and Devonian metasedimentary rocks informally referred to as the New Hampshire sequence. In addition, the rocks are intruded by granitic dikes of the Devonian New Hampshire Plutonic Suite and, at Mount Ascutney, the Cretaceous White Mountain Plutonic - Volcanic Suite. The primary purpose of this report is to present preliminary results on the stratigraphic and structural relationships in the Connecticut Valley and New Hampshire sequence rocks.