 Data from a total of 1,814 gravity observations were used in compiling the Danville-Dan River basin contour map. Of these, 269 generally utilized bench marks for elevation control and were published as part of a Virginia statewide survey (Johnson, 1971, 1972). In addition to the previous Virginia network of statewide survey points, 1,392 new measurements were recorded at sites where spot elevations (usually at road intersections) could be established using U.S. Geological Survey 7.5-minute quadrangle maps. Another 153 observations were recorded at approximately 1,300-foot intervals along segments of U. S. Highways 29, 58, and 501 and State Highway 40 located in the project area.
A total of 389 gravity observations were used in the compilation of the Scottsville basin contour map. Of these, 104 generally utilized bench marks for elevation control and were published as part of a statewide survey (Johnson, 1971). In addition to the statewide survey points, 256 new measurements were recorded at sites where spot elevations (usually at road intersections) could be established using U.S. Geological Survey 7.5-minute quadrangle maps. Another 29 observations were recorded at approximately 1,300-foot intervals along segments of State Highway 6 located in the project area.
By Stanley S. Johnson, Leonard S. Wiener and James F. Conley. 1985. Approximate size 40"x45". Scale - 1:125,000.
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