[by C.S. Coleman ... and others ; Correlation by G.H. Robinson] ; United States Department of Agriculture, Soil Conservation Service in cooperation with Virginia Agricultural Experiment Station
[by J.W. Clay ... and others] ; United States Department of Agriculture, Soil Conservation Service in cooperation with Virginia Agricultural Experiment Station
[by H.C. Porter ... and others ; Correlation by W.E. Hearn and W.S. Ligon] ; United States Department of Agriculture, Soil Conservation Service in cooperation with Virginia Agricultural Experiment Station