1884. Johns Hopkins University, Nell, Louis, U.S. Coast and Geodetic Survey, and Webster, Albert L. Depths shown by soundings and isolines. "Contours in water one fathom apart." 1 map: col., mounted on cloth; 60 x 60 cm.
1916. Research Data Services (RDS), Columbia University Libraries and Maryland Geological Survey. This is a scanned version of the 1916 paper map entitled: Baltimore and Vicinity. The map was scanned at 300 dots per inch and is in the TIFF format. Maryland Geological Survey.
1918. Maryland Geological Survey. Printed by A. Hoen and Company. Contour interval 20 feet. Datum is mean sea level. Gives routes through Baltimore for Washington, D.C. and Camp Mea... [Reston, Va.] : U.S. Geological Survey, 1918.
1892. Geological Survey (U.S.). Companion text: Guide to Baltimore; with an account of the geology of its environs and three maps : American Institute of Mining Engineers, Baltino... [Reston, Va.] : U.S. Geological Survey, 1892.