Geology of Sagamore Hill National Historic Site, New York

Part of the NPS Geodiversity Atlas, which describes each park's significant geologic features and processes. Geodiversity is the full variety of a park's natural geologic resources — rocks, minerals, sediments, fossils, landforms and physical processes — and its soils. The atlas comes from the NPS Geologic Resources Inventory and supports education, geoconservation, and management of the living and non-living parts of the ecosystem.

The park's Geologic Resources Inventory report. Image from the NPS's page.

The park

Sagamore Hill National Historic Site is on Oyster Bay, on northern Long Island in Nassau County, New York. It was Theodore Roosevelt's home from 1885 until his death in 1919, and the "Summer White House" while he was president. Established on July 10, 1963, the site protects about 33 hectares (83 acres) of the estate and its natural surroundings.

Roosevelt sketched the house himself, and it was built in 1885: a Queen Anne home of 23 rooms, with almost all of its furnishings original. The site's great natural value lies in its range of habitats — oak–tulip forest, meadows, ponds, salt marshes and beaches — home to many plants and animals. Visitors can tour the house, walk the nature trail, picnic, and explore the Oyster Bay area.

The Roosevelt home. Image from the NPS's page.

Geologic setting

The site is in the Coastal Plain physiographic province. Its geology is young, fairly flat-lying sediment — gravel, sand, silt and mud, loose to partly consolidated — that coastal processes constantly rework.

Much of the site, including the estate grounds, is Harbor Hill ground moraine: rock and soil debris that glaciers deposited as they retreated north, during the Quaternary (about 75,000–11,000 years ago). The easternmost part, along Cold Spring Harbor, holds marsh deposits of similar age.

The site shares its geologic history and some characteristic formations with the rest of the Coastal Plain, a region reaching far beyond the park.

Maps and reports

The Geologic Resources Inventory produces digital geologic maps and reports for more than 270 natural resource parks:

• Scoping summaries record the meetings at which NPS staff and local geologists set each park's mapping plan and report content.
• Digital geologic maps come with a user guide and supporting map information; newer ones include Google Earth and online map services.
• Reports use the maps to discuss the park's setting and significance, notable features and processes, resource management issues, and geologic history.
• Posters show the map data as PDFs, newer ones with aerial imagery or shaded relief.

The products for Sagamore Hill are in the NPS DataStore. A Soil Resources Inventory project for the site has also been completed and is in the DataStore.

The wetlands boardwalk after Hurricane Sandy, October 2012. Image from the NPS's page.

More: Sagamore Hill National Historic Site · Beaches and coastal landforms · Geologic time · the Geodiversity Atlas.

Sources

Based on "NPS Geodiversity Atlas—Sagamore Hill National Historic Site, New York," National Park Service; a work of the United States government in the public domain. The site's geomorphological map, credited on its face to authors at Rutgers University's Institute of Marine and Coastal Sciences, is not reproduced.