GEOPHYSICAL PROSPECTION: FINDING FORT DEFIANCE AT THE HISTORIC SITE IN LENOIR, NORTH CAROLINA

Fort Defiance is a historic site in Lenoir, North Carolina offering tours to local school groups and visitors from around the world. The site includes the plantation house and outbuildings constructed by William Lenoir between 1788-1792 in the fertile Happy Valley near the Yadkin RIver. Lenoir, a statesman and a scholar named his home Fort Defiance after the pioneer fort built before the American Revolution and used to protect settlers during the Cherokee War in 1776. Today, there is no trace of the fort although it is reported to have stood nearby.

We used ground penetrating radar (GPR) and magnetometer to detect anomalies that were compared with archaeological excavations and reconstruction of frontier forts in the southeastern United States to identify the footprint of Fort Defiance. A GPR survey with a 350 mHZ hyperstacking antenna covered 0.85 acres at 1 ft transect spacing. Gradiometer data was collected with a GEM Systems GSM-19W Overhauser gradiometer.

The GPR data imaged a continuous linear set of reflections measuring 80 x 100 ft. A linear reflection-free anomaly parallels the linear reflections and could represent the palisade trench. It’s width (~2 ft) and depth (~3 ft) are similar to the trench that held 10 ft tall palisade posts constructed by Moravian pioneers at Bethabara (near Winston-Salem) in 1756. Soil borings along the anomaly collected quartz river rocks that may have been added to stabilize the log posts within the trench. Most forts are built with bastions that extend beyond the palisade wall to provide a line of sight for defense. At Fort Defiance, the bastions appear to be blockhouses that are imaged as linear high-amplitude rectangular sets of that may represent a rock foundation. These substantial structures could have extended high enough above the palisade to act as a lookout across the valley. Plow scars mask much of the magnetic data collected to date. However, a subtle magnetic anomaly along the interpreted palisade wall can be traced across a hillshade image of the magnetic data. A direct-current electrical resistivity survey is planned to add additional information regarding the properties of the materials within the trench and blockhouse foundations.