American coastal defence Third System forts: how geomorphology and geology dictated placement and influenced history
Published:January 01, 2019
Stephen W. Henderson, 2019. "American coastal defence Third System forts: how geomorphology and geology dictated placement and influenced history", Military Aspects of Geology: Fortification, Excavation and Terrain Evaluation, E.P.F. Rose, J. Ehlen, U. L. Lawrence
Download citation file:
In total, 42 Third System forts were built along the east coast of the USA between 1816 and 1867. Because of their purpose, to defend key locations against potential British amphibious assault, their sites were limited to islands, shoals, shorelines, riverbanks or hilltops. Sited along the Atlantic and Gulf of Mexico coastlines, many are constructed upon distinctive geomorphological landforms that are related more to features influenced by Quaternary glaciation or sea-level changes than by pre-Quaternary bedrock. A selection of forts is described to illustrate the principal geological and geomorphological features that influenced their construction: at Boston Harbor in Massachusetts on drumlins, near New York City on moraine and at Fort Pulaski protecting Savannah Harbor in Georgia on saltmarsh. Further south, Fort Clinch in northern Florida, forts guarding Pensacola Bay in western Florida and the entrance to Mobile Bay in the Gulf region, and Fort Massachusetts on Ship Island, Mississippi, were all primarily situated on Holocene barrier islands. Construction, use and 1861–65 Civil War threats to these forts can be directly related to their geomorphological context. Although all are now redundant, most remain as a remarkable and highly visible aspect of the military history of the USA.
Figures & Tables
Military Aspects of Geology: Fortification, Excavation and Terrain Evaluation
CONTAINS OPEN ACCESS
This book complements the Geological Society’s Special Publication 362: Military Aspects of Hydrogeology. Generated under the auspices of the Society’s History of Geology and Engineering Groups, it contains papers from authors in the UK, USA, Germany and Austria. Substantial papers describe some innovative engineering activities, influenced by geology, undertaken by the armed forces of the opposing nations in World War I. These activities were reactivated and developed in World War II. Examples include trenching from World War I, tunnelling and quarrying from both wars, and the use of geologists to aid German coastal fortification and Allied aerial photographic interpretation in World War II. The extensive introduction and other chapters reveal that ‘military geology’ has a longer history. These chapters relate to pre-twentieth century coastal fortification in the UK and the USA; conflict in the American Civil War; long-term ‘going’ assessments for German forces; tunnel repair after wartime route denial in Hong Kong; and tunnel detection after recent insurgent improvisation in Iraq.