From the site: "This map includes short descriptions of geologic units and a cross section showing the distribution of geologic units under the earth’s surface. Among other uses, the map will provide users with a better understanding of the distribution, depths and thickness of Marcellus Shale. This map will be especially useful in showing the interplay between geologic formations and groundwater availability and quality.

The map updates geologic information to be consistent with adjacent states, redefines boundaries between formations from the previous maps, and updates the subsurface geologic cross section based on new review of geologic cores and geophysical logs. The geologic information is available to users in Geographic Information System (GIS) format. A printable PDF version is also available. At this time we do not plan to offer a printed version of this map. The map is about 36 inches high by 60 inches wide when printed. If you do not have access to a large-format printer you can take the PDF file to a desktop publisher or office supply store and have it printed.

This product was assembled at a scale of 1:100,000. Using the map or data a smaller scale, such as 1:60,000 or 1:24,000, can result in serious positional errors. All data, information, and maps are provided "as is" without warranty or any representation of accuracy, timeliness of completeness. The burden for determining accuracy, completeness, timeliness, merchantability and fitness for or the appropriateness for use rests solely on the user. Maryland Department of Natural Resources makes no warranties, express or implied, as to the use of the information obtained here. There are no implied warranties of merchantability or fitness for a particular purpose. The user acknowledges and accepts all limitations."