00956cam a22002531i 4500001001300000003000400013005001700017008004100034010001700075035001900092040003100111050002200142051001600164082000800180086001600188100004000204245018700244260004900431300005900480410005700539650003300596650004200629650003100671gs 52000105 DLC20260227111358.0780316s1950    dcuab        f000 0 eng    ags 52000105   a(OCoLC)3723994  aDLCcOClUdISSdOCoLCdDLC00aQE75b.P9 no. 217  aQE445b.D25  a5520 aI 19.16:2171 aDarton, Nelson Horatio,d1865-1948.10aConfiguration of the bedrock surface of the District of Columbia and vicinity.cThis report embodies subsurface data of interest to engineers and builders compiled from 1890 to 1940.  aWashington :bU.S. Govt. Print. Off.,c1950.  a42 p. :bill., maps (part col., 4 in pocket) ;c29 cm.20aGeological Survey (U.S.).tProfessional paper ;v217 0aPetrologyzWashington (D.C.) 0aPhysical geographyzWashington (D.C.) 0aBoringszWashington (D.C.)