THE GEOHERITAGE OF SARATOGA NATIONAL HISTORICAL PARK: HOW GEOLOGY IMPACTED THE BATTLES OF SARATOGA, THE AMERICAN REVOLUTIONARY WAR, AND THE AMERICAN IDENTITY

Saratoga National Historical Park is located along the upper Hudson River Valley of east-central New York and was established to commemorate the Battles of Saratoga that took place during the American Revolutionary War. Fought on 19 September 1777 (Battle of Freeman’s Farm) and 7 October 1777 (Battle of Bemis Heights), the Battles of Saratoga resulted in the first significant American military victory over the British. The surrender of British forces following the Battles of Saratoga boosted American morale and convinced France to enter the war on behalf of the United States. The geology of the historical park is integral to its history and cultural identity but also influenced the outcome of the battles, the destiny of the war, and the fate of the fledgling American colonies.

The geology of the Hudson River Valley played a crucial role in the Battles of Saratoga, as the historic river corridor predetermined the location of combat and influenced military strategy (both American and British) as well as the resulting surrender of British forces. Situated along the Taconic orogenic front, the bedrock underlying the historical park consists of Ordovician flysch and mélange that control the course of the Hudson River. Topographic vantage points along the uplifted Taconic front were also utilized by spies to survey troop movements and positions. Paleozoic strata are unconformably overlain by Pleistocene sediments that record the progressive deglaciation of New York following the last Ice Age. These unconsolidated surficial deposits have been fluvially dissected to form the historical park’s modern landscape, including its ravines, hills, and formidable river bluffs. The success of the American military strategy relied on a critical understanding of the Hudson River’s role in the British campaign, especially its movement of troops, supplies, and weapons. To prevent the British advance, the American army fortified the narrow floodplain as well as the bluffs and forested upland hills flanking the river–defensible positions consisting of glaciolacustrine deposits and glacial till, respectively. Following the Battles of Saratoga, the American occupation of tectonic and glacial landforms prevented the British retreat and forced a historic surrender that echoes through time.