Ludlovian Stage

(or Ludlow; named after Ludlow in the county of Shropshire, Great Britain), the third stage from the bottom of the Silurian system. It was identified by the English geologist R. Murchison in 1833. Deposits of the Ludlovian stage are subdivided into the Elton, Bringewood, Leintwardine, and Whitcliffe beds. The Ludlovian stage is characterized primarily by benthic fauna and corresponds to four graptolitic zones: Monograptus nilssoni, M. scanius, M. tumescens, and M. leintwardinensis. In the USSR deposits of the Ludlovian stage occur in both shell and graptolitic facies (in the Baltic region, the southwestern Ukraine, Novaia Zemlia, the Urals, Middle Asia, Kazakhstan, the Altai, and the Tuva ASSR).