A survey of Valley Forge National Historical Park was carried out by MASCA in 1978 for the National Park Service utilizing, among other techniques, aerial photography, the cesium magnetometer, and ground penetrating radar. The aim of the project was to locate evidence of the encampment of 1777-78 using for the most part non-destructive methods. Hut sites and offal pits dating from the Revolutionary War period were identified. A major problem in interpreting the data from the various techniques employed was the amount of modern disturbance at the park. See AATA 17-159.