Hydrologic investigations and field reconnaissance for the 1:50,000 scale map of Syria provided more detailed information on the exact stratigraphic position, quality, and extent of the phosphate deposits. The deposits are found in strata of Santonian through Eocene age, as well as in Holocene deposits in the southern part of the region. Santonian phosphates are limited to the central part of the southern Palmyride chain. Campanian phosphorites are well-developed and represented by rocks primarily composed of calcium phosphate. The major Maestrichtian phosphate deposits occur in the southern Palmyrides. Lower Danian phosphate is known only in the Ghadir el-Hamal. Paleocene phosphates are found on the flank of Mount Abou Rabah and Jabal Ash-Sheikh. Middle Eocene phosphorites are found in thin, localized bands, and in carbonate and glauconite beds. Upper Eocene phosphorites also occur in the southern Palmyrides. Holocene phosphates are represented by phosphatized bone accumulations.