Companion text: Guide to Baltimore; with an account of the geology of its environs and three maps : American Institute of Mining Engineers, Baltinore meeting, 1892 / prepared by a local committee for the use of the American Institute of Mining Engineers. 1892. Map Room does not have the text that accompanies this map. Includes color-coded legend of types of sediment. Surveyed in 1887, 1890, and 1891. Relief shown by contours.