Portlandian Stage

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Portlandian Stage

 

the upper stage of the Jurassic system. It was identified in 1842 by the French geologist A. d’Órbigny on the Isle of Portland, a peninsula in southern Great Britain. In its stratotype it is represented by shallow-water marine deposits—clays, glauconitic sands, and sandstones in the lower strata and limestones in the upper. In the Mediterranean region, the Crimea, and the Caucasus the Portlandian stage is referred to as the Tithonian stage; on the East European Platform the deposits of the Volga stage correspond to the Portlandian stage.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.