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Geologic sections (C-C', D-D', and E-E') illustrating the general distributions and thicknesses of seismic stratigraphic units and major unconformities in the Martha’s Vineyard and Nantucket study areas. The geologic sections were produced from chirp seismic-reflection profile interpretations.The Ul unconformity is a dashed line to denote that it is discontinuous and/or inferred.