Geology, which was of far-reaching importance on the Western Front of World War I, played a less spectacular role during World War II in so far as the United States armies in Europe were concerned. The U. S. Army in the European Theater of Operations (ETO) used geologists in two capacities: (1) to make staff studies at the level of Theater Headquarters, and (2) as officer personnel in a water-supply unit. In the first category, only one group of seven geologists was employed, forming part of the Information Section, Intelligence Division, Office of the Chief Engineer, ETO. The products of this group consisted largely of regional and localized terrain (trafficability) studies that ranged geographically from the Normandy invasion beaches to Czechoslovakia. Problems of water supply, sources of road material, and many other questions of a geologic nature also arose. French geologists collaborated closely with the work of the section. As the campaign progressed, the Military Geology Unit of the U. S. Geological Survey made important contributions to the geologic intelligence of Germany.