Geodiversity Atlas—National Capital I&M Network Index

Geology and Stratigraphy of the National Capital Region I&M Network

The National Capital Region Inventory & Monitoring Network (NCRN) consists of 11 national park units in Maryland, Virginia, Washington, D.C., and West Virginia. These park units include Antietam National Battlefield (ANTI), Catoctin Mountain Park (CATO), Chesapeake and Ohio Canal National Historical Park (CHOH), George Washington Memorial Parkway (GWMP), Harpers Ferry National Historical Park (HAFE), Manassas National Battlefield Park (MANA), Monocacy National Battlefield (MONO), National Capital Parks-East (NACE), Prince William Forest Park (PRWI), Rock Creek Park (ROCR), and Wolf Trap National Park for the Performing Arts (WOTR). The parks that comprise the National Capital Region Network protect a combined 29,468 hectares (72,818 acres) varying in size from 52 hectares (130 acres) in WOTR to 7,936 hectares (19,612 acres) in CHOH.

The geology of the NCRN forms the foundation of a diverse landscape consisting of parks, forest, parkways, trails, monuments, memorials, historic sites, scenic areas, parks for the performing arts, and Civil War-era battlefields. The bedrock underlying the park units of the NCRN dates back to the Mesoproterozoic and records the rich geologic evolution of eastern North America over hundreds of millions of years. Significant geologic events during this time include the opening of the ancient Iapetus Ocean to form the Atlantic Ocean, formation of the Appalachian Mountains, rifting of the supercontinent Pangaea, and subsequent erosion and modification by surface processes to form the modern landscape. See also, Geologic Time Scale - Geology (U.S. National Park Service).

The parklands of the NCRN occur in all of the major physiographic provinces of the central Appalachian region except the Appalachian Plateaus Province. The NCRN parks occur in the following provinces (from east to west): 1) Coastal Plain; 2) Piedmont; 3) Blue Ridge; and 4) Valley and Ridge. The Coastal Plain Province has the lowest topographic relief of these provinces and consists of undeformed, unconsolidated sedimentary rocks and deposits that are separated from deformed, metamorphic rocks of the Piedmont along a transitional boundary known as the “Fall Line”. The Blue Ridge Province is characterized by a highland composed of crystalline, quartz-rich and erosion-resistant metamorphic rocks. The Valley and Ridge and Piedmont Provinces are characterized by low, rolling hills punctuated by a steep gorge along the Potomac River (Southworth and Denenny 2006). The varied geologic history created a wide variety of rocky types and exposures throughout the NCRN that geologists have used as the basis of geologic maps for more than 200 years. Many of the rocks also contain fossils as summarized by Kenworthy and Santucci (2004).

A Brief Geologic History

A few examples of events and Network resources in each geologic time period are highlighted below, from youngest to oldest.

• See also, Geologic Time Scale - Geology (U.S. National Park Service)

Geology & Soils—National Capital Region Network Parks

Type Sections—National Capital Region Network

The geologic history above is excerpted from a report titled, "National Park Service geologic type section inventory: National Capital Region Inventory & Monitoring Network". Type sections are essential reference locations for the geoscientists who study geologic history and paleontology. A summary of the type sections in each park can be found at the links below.

• Antietam National Battlefield, Maryland (no designated stratotypes identified)

• Catoctin Mountain Park, Maryland (no designated stratotypes identified)

• Chesapeake and Ohio Canal National Historical Park, Washington D.C., Maryland, and West Virginia (contains 14 identified stratotypes)

• George Washington Memorial Parkway, Washington D.C., Maryland, and West Virginia (contains one identified stratotype)

• Harpers Ferry National Historical Park, West Virginia, Virginia, and Maryland (contains four identified stratotypes)

• Manassas National Battlefield Park, Virginia (contains two identified stratotypes)

• Monocacy National Battlefield, Maryland (contains one identified stratotype)

• National Capital Parks-East, District of Columbia (contains one designated stratotype)

• Prince William Forest Park, Virginia (contains two identified stratotypes)

• Rock Creek Park, District of Columbia (no designated stratotypes identified)

• Wolf Trap National Park for the Performing Arts, Virginia (no designated stratotypes identified)

The full Network report is available in digital format from:

• DataStore - National Park Service geologic type section inventory: National Capital Region Inventory & Monitoring Network (nps.gov)

Please cite this publication as:

• Henderson TC, Santucci VL, Connors T, Tweet JS. 2022. National Park Service geologic type section inventory: National Capital Region Inventory & Monitoring Network. Natural Resource Report. NPS/NCRN/NRR—2022/2422. National Park Service. Fort Collins, Colorado.

NPS Stratotype Inventory

Fossil Resources—National Capital Region Network

Between 2002 and 2011, network-based paleontological resource inventories were completed for all the 32 I&M networks, and six of the earliest were completely updated between 2012 and 2016. The report linked below summarizes the paleontological resources of all park units in the National Capital Region Inventory & Monitoring Network (NCRN). The report provides geologic background and paleontological resource data for each park to support management operations, planning, and science-based decision making as required by NPS management policies and the Paleontological Resources Preservation Act (2009).

The full report is available in digital format from

• DataStore - Paleontological Resource Inventory and Monitoring, National Capital Region (nps.gov)

Please cite this publication as:

• Kenworthy, J.P. and V. L. Santucci. 2004. Paleontological Resource Inventory and Monitoring, National Capital Region. National Park Service TIC# D-289.

Related Links

• National Capital Inventory & Monitoring Network
• NPS Geodiversity Atlas
• NPS—Geologic Resources Inventory

Geodiversity Atlas pages—by Inventory & Monitoring Network

Geodiversity Atlas pages—by State, U.S. Commonwealth, and Territories