The purpose of this investigation which is being made in cooperation with the Georgia Department of Mines, Mining and Geology, Chatham County, and the City of Savannah, is to determine whether salt-water encroachment has occurred in the principal limestone aquifer in the Savannah area, and, if so, to delimit the extent of the encroachment vertically and laterally. The drilling of two test wells, which constitutes the initial part of the investigation, was done in April, May, and June, 1954. This interim report describes the subsurface geology in the Savannah area and reports the results of water samples taken during the test drilling. The investigation is being continued by M. A. Warren and F. B. Hudson of the U.S. Geological Survey, and later results will be given in a subsequent report.