Report of progress in the Venango county district. [electronic resource] By John F. Carll. Observations on the geology around Warren. By F. A. Randall. Note on the comparative geology of northern Ohio and north-western Pennsylvania and western New York. By J. P. Lesley.
Harrisburg, Pub. by the Board of commissioners for the Second geological survey, 1875.
At head of title: Second geological survey of Pennsylvania: 1874.
Folded plate and maps in pocket.
Electronic text and image data. Ann Arbor, Mich. : University of Michigan, Digital Library Initiatives, 2000. Includes both TIFF files and keyword searchable text. [Making of America] This volume is made possible by a grant from the Andrew W. Mellon Foundation as part of Making of America IV: the American voice, 1850-1877.