Delaware Geological Survey releases new geologic map of Harbeson area

The Delaware Geological Survey (DGS) has published a new geologic map of the area east of Georgetown in Sussex County entitled Geologic Map of the Harbeson Quadrangle, Delaware. Geologic Map 17 presents the results of research by Kelvin W. Ramsey and Jaime L. Tomlinson of the DGS.

The map shows and describes the geologic units found at the land surface and in the shallow subsurface in the map area. The map includes cross sections that show stratigraphic units that lie beneath the surficial units and detailed descriptions and ages of all units presented on the map.

Geologic maps provide valuable information for land-use planning and managing natural resources, which is particularly important in a rapidly growing area such as eastern Sussex County. The purpose of Geologic Map No. 17 is to compile fundamental geologic data from this area in map form that can be used as a basis for land-use decisions, environmental studies such as assessing the suitability of sites for land-based wastewater disposal, and identification of natural resources such as groundwater, sand, and gravel.

In the Harbeson area, water-bearing sands in the Beaverdam Formation function as a major shallow aquifer for potable and agricultural water supplies. This geologic map can be used to aid in locating water supplies for public, domestic, agricultural, and industrial use, mapping groundwater recharge areas, and protecting both groundwater and surface-water resources.

The map is part of the Delaware Geological Survey’s ongoing mission to understand geologic and hydrologic systems and to advise, inform, and educate Delawareans about the results of such investigations for use in issues regarding surface and groundwater resources, agriculture, economic development, land-use planning, environmental protection, resource evaluation, engineering applications, hazard identification and mitigation, and recreation.

DGS Geologic Map No. 17 is available as a PDF to view online or as a downloadable product from the DGS web page. Printed copies may be requested by contacting DGS at 302-831-2833, via email at, or by visiting the DGS office at the University of Delaware.

For questions and information, contact DGS at, 302-831-2833