1. Subsurface correlations and sequence stratigraphic interpretations of lower Silurian strata in the Appalachian Basin of northeast Ohio, southwest New York, and northwest Pennsylvania [electronic resource] Yale Public content 2001. 2002-06-01T04:00:00Z. 2003-10-26T22:59:41Z. Geological Survey (U.S.). The Survey. English. Public. Northeastern States. Silurian.