The objective was to determine the availability and costs of limestone and similar materials throughout the contiguous United States, thus providing a basis for determining the feasibility and economics of limestone-based SO2 removal processes for any particular power plant site. Materials covered include limestone, dolomite, chalk, marble, marl, and shell. Information is presented on location of deposits, production rates, F.O.B. quarry costs, transportation methods and costs, expected cost increases, uses, chemical composition, and physical properties. Much of the data is reported nationally, regionally, and on a state-wide basis. The regions were chosen to coincide with those defined by the National Coal Association. The major deposits of carbonate rocks occur in the eastern half of the United States, where the vast majority of fossil fuel-fired power plants are located. Limestone is the only type of carbonate rock which is produced in large enough quantities to merit consideration for widespread application. (Author)