Ashgill Layer

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 It might be outdated or ideologically biased.

Ashgill Layer

 

(named after the settlement of Ashgill, Great Britain), the uppermost layer of the Ordovician system. In typical locations it is composed of shalelike clays with trilobites and graptolites. It is divided into two zones according to the graptolite composition: Dicellograptus complonatus and D. anceps. Deposits of the Ashgill layer are known in Western Europe, non-Soviet Asia, and North America; in the USSR they are found in Kazakhstan, Siberia, and the northeast.

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