Buchak Strata

(named for the village of Buchak, Cherkassy Oblast, Ukrainian SSR), a local subdivision of the Paleogene of the Ukraine established in the Dnieper region by the geologist N. A. Sokolov in 1893. In the Left-bank Ukraine the strata are 10-to-12 m thicknesses of clayey glauconites and white quartz sands, which contain remains of bivalve mollusks of the mid-Eocene epoch (Cardium semigranulatum and Venericardia pulchra, among others). In the Right-bank Ukraine the strata are composed of continental deposits (kaolin clays, lignite, and others).