Bedrock geologic maps show the type, age and distribution of bedrock near the earth’s surface. In other words, the maps depict the bedrock that would be exposed at the earth’s surface if the soil and vegetation were completely removed.  Each rock unit is identified and named based on distinctive characteristics that can be mapped over large distances. Bedrock geologic maps also show geologic structures such as faults, fractures and folds. Each map is provided with a written explanation and legend that describes the rocks, structures, history of deformation, tectonic setting and any economic potential.

Below is an example bedrock geologic map of the Goshen quadrangle (Franklin and Hampshire Counties, Massachusetts).  Clicking on a particular zone of the map will pop up a zoomed-in view of that zone in a new browser window.  When reconstructed, the whole image is 3193x2458 pixels in size, or approximately 44” x 34” in real life at 72 dpi.