Illinois-Wisconsin, Pecatonica quadrangle.

Chicago citation style
Geological Survey (U.S.). Illinois-Wisconsin, Pecatonica quadrangle.. 1936. Retrieved from the Digital Public Library of America, https://digital.library.illinois.edu/items/99083f40-82d4-0134-1f08-0050569601ca-0. (Accessed April 17, 2021.)
APA citation style
Geological Survey (U.S.), (1936) Illinois-Wisconsin, Pecatonica quadrangle.. Retrieved from the Digital Public Library of America, https://digital.library.illinois.edu/items/99083f40-82d4-0134-1f08-0050569601ca-0
MLA citation style
Geological Survey (U.S.). Retrieved from the Digital Public Library of America <https://digital.library.illinois.edu/items/99083f40-82d4-0134-1f08-0050569601ca-0>.
Note: These citations are programmatically generated and may be incomplete.