The large boulder, located just south of here, served as an important landmark during the Civil War, when Col. John S. Mosby's Partisan Rangers (43d Battalion, Virginia Cavalry) assembled there to raid Union outposts, communications, and supply lines. Laura Ratcliffe, a young woman who lived nearby and spied for Mosby, concealed money and messages for him under the rock. Mosby credited her with saving him from certain capture by Federal cavalry on one occasion. She also was a friend of Maj. Gen. J.E.B. Stuart.