Geologic mapping is at the core of DGS research activities. Geologic maps provide a map-based representation of our current understanding of the geology of Delaware. Geologic maps can be made at several scales, depending on the level of detail of the underlying data and on intended use of the map. Most maps in the DGS Geologic Map Series focus on surficial geology, but subsurface geologic mapping is also part of our program.

The Delaware Geological Survey (DGS) began publishing the geologic map series in 1970. Geologic maps 1 to 9 were published with traditional hand drafting and printing of geologic boundaries and U.S. Geological Survey (USGS) topographic Mylar base maps. DGS moved toward digital publication in the 21st century. Geologic map 12 polygons were digitized in ArcInfo® 8, and USGS topographic Mylar maps were scanned and georeferenced for the base map. These digital layers were compiled in Adobe Illustrator 9 for final publication format. Future DGS map publications will use Delaware Spatial Data Framework layers for digital base map data.

The publication can be obtained as a PDF at GM1 Geology of the Chesapeake and Delaware Canal Area, Delaware.