Comparison of Permian ammonoid zones of Soviet Russia with those of North America

In this paper an attempt is made to summarize briefly the available data in regard to the Permian ammonoid zones represented in Soviet Russia, and to compare them with the familiar western Texas zones. It is pointed out that the Wolfcamp horizon (zone of Properrinites) is represented in the Urals and in Crimea; the Leonard horizon (zone of Perrinites) is represented in the Urals, the Pamirs, and Darwaz; and the Word horizon (zone of Waagenoceras) is represented in Crimea and the Pamirs. No ammonoids are known from the Capitan horizon (zone of Timorites) in the U.S.S.R.