County Rock Type Maps of Pennsylvania
Pennsylvania has a great diversity of bedrock types. In the southeastern part of the state, there are crystalline (igneous and metamorphic) rocks. A band of mostly red sedimentary rocks with multiple bodies of igneous rocks that were intruded into them extends from Adams to Bucks Counties. The remainder of the state is underlain by sedimentary rocks of practically all types. Much of the state is mantled with unconsolidated rocks up to 600 feet thick. The logs of water wells penetrating the rocks of Pennsylvania have many uses. The more accurate and complete the logs are, the more useful they are.
This web page provides page-sized maps (PDF) by county showing where various rock types are present in Pennsylvania. The maps are based on Map 63, which is available online. These maps are derivatives of Map 63 and are intended as a regional maps that show broad trends and patterns. They are not intended for detailed analysis or site-specific applications (e.g., permitting). Map 63 delineated 19 different rock types for Pennsylvania. Rock type descriptions are abbreviated on the maps; full descriptions of the 19 rock types are provided along with a glossary.
Use the list or click on the state map below to open a county map as a PDF*. All maps open in a new window.