C.V. Theis 1934 Following a request from the U.S. Bureau of Biological Survey, the writer was assigned by the Director of the U.S. Geological Survey to make a preliminary geological investigation of the Salt Plains area in Oklahoma. He spent the period from January 13 to January 22, 1934, in the field making this study. (available as photostat copy only) application/pdf 10.3133/ofr342 en Preliminary geological report on the Salt Plains reservoir site, Oklahoma reports