CHALKSTONES, a white to grayish loosely coherent limestone (calcium carbonate) consisting of the calcareous remains of minute marine organisms and fine grained calcium carbonate of uncertain origin together with subordinate amounts of shell fragments, varying proportions of clayey and sandy material and flint (q.v.) nodules. It forms thick and extensive beds in various parts of the world including the Belqa Series (Upper Cretaceous—Eocene, 88-38 million years) of the Holy Lands. Chalks and chalky limestones of the Belqa Series occur in northern Samaria and parts of western Galilee and over large areas of Jordan E of the Jordan Rift Valley. Here isolated flat-topped hills, generally capped with harder chalk beds, rise from the plain where the chalk has been largely eroded by wind, leaving behind flint gravels. This softness and lack of resistance to erosion would account for the reference in Isaiah 27:9.

Bibliography E. M. Blaiklock (ed.), The Zondervan Pictorial Bible Atlas (1969), 438-452.