Cite

Second geological survey of Pennsylvania : geological map of Berks County / J.P. Lesley, state geologist, compiled from the surveys of F. Prime, E.V. D'Invilliers, R.H. Sanders.

MLA

of Pennsylvania, Geological Survey. Second Geological Survey of Pennsylvania : Geological Map of Berks County / J.P. Lesley, State Geologist, Compiled from the Surveys of F. Prime, E.V. D'Invilliers, R.H. Sanders. Second Geological Survey of Pennsylvania, 1884. https://collections.library.yale.edu/catalog/15811135.

APA, 6th edition

of Pennsylvania, G. S. (1884). Second geological survey of Pennsylvania : geological map of Berks County / J.P. Lesley, state geologist, compiled from the surveys of F. Prime, E.V. D'Invilliers, R.H. Sanders. [Maps]. Second Geological Survey of Pennsylvania, https://collections.library.yale.edu/catalog/15811135.