00985cam a22002651i 4500 gs 52000105 DLC 20260227111358.0 780316s1950 dcuab f000 0 eng gs 52000105 (OCoLC)3723994 DLC OClU ISS OCoLC DLC QE75 .P9 no. 217 QE445 .D25 552 I 19.16:217 Darton, Nelson Horatio, 1865-1948. Configuration of the bedrock surface of the District of Columbia and vicinity. This report embodies subsurface data of interest to engineers and builders compiled from 1890 to 1940. Washington : U.S. Govt. Print. Off., 1950. 42 p. : ill., maps (part col., 4 in pocket) ; 29 cm. Geological Survey (U.S.). Professional paper ; 217 Petrology Washington (D.C.) Physical geography Washington (D.C.) Borings Washington (D.C.) 28630 28630