"Note: This map is reduced from surveys made ... between 1850 and '57 ... and from supplementary surveys of the interior made ... in 1867 and '68 ... The scale of the original maps is 1:10,000."
"Plate no. 1179."
"Electrotype copy no. 1, U.S.C.S."
Contour interval 20 ft.
Also available on the Internet through the American Geographical Society Library Digital Map Collection.