A summary of past investigations in Utah and a description of the work done during the 1934-36 biennium are included in the State Engineer’s Twentieth Biennial Report (pp. 91-106). Co-operative investigation with the State Engineer, begun on July 1, 1935, has been continued during the past biennium. To provide for this work, the 1935 Utah State Legislature appropriated \$10,000 to the State Engineer, this sum being matched by the U. S. Geological Survey during the biennium ending June 30, 1937. During its 1937 session the State Legislature appropriated \$5000 for continuation of co-operative work in underground waters. An equal sum was provided by the U. S. Geological Survey and investigations have continued during the fiscal year ending June 30, 1938.