"Structure" is one of four layers which\\ncollectively describe the subsurface geologic formation, structural geology and\\nsurficial deposits. "Structure" is the point file of geologic strike\\nand dip as determined from outcrops. The geology of Loudoun County, Virginia, was\\nmapped in 1988 through 1991 under a cooperative agreement between the U.S.\\nGeological Survey (USGS) and the Loudoun County Department of Environmental\\nResources. This geologic map was compiled in 1993 from a series of detailed\\npublished and unpublished field investigations at scales of 1:12,000 and\\n1:24,000. Some of these same data were compiled as a digital geologic map at\\n1:100,000 scale (Burton and others, 1992a) and were the basis for a\\ncost-benefit analysis of the societal value of geologic maps (Bernknopf and\\nothers, 1993). The data was later revised and published by USGS in the Open\\nFile Report, MAP OF-99-150, GEOLOGIC MAP OF LOUDOUN COUNTY, VIRGINIA By Scott\\nSouthworth, W.C. Burton, J.S. Schindler, and A.J. Froelich1 with contributions\\non the geology of the Piedmont province by A.A. Drake, Jr., and R.E. Weems and\\nan aeromagnetic survey by D.L. Daniels, W.F. Hanna, and R.E. Bracken.