Paleontological resource site condition assessment: Fort Washington Park (National Capital Parks-East)

Clites, Erica; Santucci, Vincent

This report provides baseline paleontological resource data to National Park Service administration and resource management staff. The report contains information regarding the location of non-renewable paleontological resources within NPS units. It is not intended for distribution to the general public. Fort Washington Park has been known as a fossil collecting site for almost 200 years, but the condition of the fossil sites has not been assessed prior to this study. A paleontological resource scoping meeting and field visits were conducted July 7, 2009 with park staff. The ravines within Fort Washington Park (FOWA) contain exposures of the fossiliferous Aquia Formation, part of the Atlantic Coastal Plain physiographic province. The Aquia Formation is probably the most abundantly fossiliferous formation within FOWA, and consists mostly of unconsolidated very-fine to fine-grained glauconitic sand, which is easily eroded. The sandstone beds (referred to as indurated layers) within the Aquia Formation can be used to correlate between ravines. Ravine B presented a resource management concern due to accelerated erosion rates removing fossil-bearing sediment. The erosion rate was documented using repeat photography. In Ravine D, internal molds of Cucullaea (a bivalve) were discovered, which did not occur in the other ravines. At least five new fossil genera were identified from field photos. Seven additional specimens are now being curated in Fort Washington Park’s museum collection at the Museum Resource Center in Landover, MD. This report also includes a site condition assessment for a portion of Piscataway Park. A fossil field trip to Fort Ravine was conducted September 9, 2009 with 20 participants. The group received an introduction to the geology of the park and visited sites with abundant fossils in Ravine A as well as examining the erosion at the head of Ravine B with NCR Regional Hydrologist. A workshop was also held for FOWA park staff and National Capital Parks-East education specialists on interpreting paleontological resources. Clites explained geologic tools such as stratigraphic columns and the geologic time scale, as well as giving examples of other park’s natural resource interpretive media. A fact sheet was created to present basic information about the fossils of Fort Washington Park and their origin. Due to the abundance of fossils in easily-eroded sediment, periodic monitoring is recommended for ravines A, B, and D. Annual monitoring to look for erosional features would be conducted in each ravine, including photographing the major exposures pictured in this report. Paleontological site monitoring will provide data on the condition of individual sites and the natural or human stressors that are impacting them. Fossil collection may be warranted where erosion rates are high to prevent the loss of fragile fossil molds. The park may also consider working with local geologists to fit the Aquia Formation exposures at Fort Washington Park into a regional context.Through a Natural Resource Program Center technical assistance request, hydrologist Gary Smillie studied the erosion occurring in Ravine B and presented the park with repair options. The park has submitted a PMIS request to conduct stabilization. A fossil exhibit is scheduled to open in the FOWA visitor center in 2012.

Paleontological resource site condition assessment: Fort Washington Park (National Capital Parks-East)

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