Introduction: This report is a summary of the field work at the Lost Creek schroeckingerite deposit, Sweetwater County, Wyo. from July 1 through November 22, 1952. The objectives of field work at Lost Creek during the report period were to obtain additional data for calculating tonnage and grade and to obtain additional information on the controls and localization of schroeckingerite. In order to accomplish these objectives the Survey continued the exploration by means of trenching, mapped all trench walls (scale 1:120), mapped the exploration area at scales of 1:2400 and 1:9600, and carried on an extensive sampling program.