Epoch, Geological

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 It might be outdated or ideologically biased.

Epoch, Geological

 

an interval of time in the earth’s geological history, during which a layer of rock that forms a series was deposited. Epochs are subdivided into ages. Two or three epochs constitute a period. (See alsoGEOCHRONOLOGY.)

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