Historical reference: Do not rely on this information. It is very old. About this collection
Colonies, in paleontology, consist, according to M. Barrande, who introduced the term in 1852 in his "Silurian System of Central Bohemia," of faunas, or assemblages of fossils which, though characteristic of some later period, occur intermingled with an earlier fauna. This he explained as due to migration under changing conditions; but, though there is undoubtedly much that is true in the general "doctrine of colonies," it has been shown that M. Barrande's instances are fallacious, being in fact owing to great inversions of strata in the Silurian rocks of Bohemia.