Bathonian_Series

Bathonian Series, in geology. The typical Bathonian is the Great Oolite series of England, and the name was derived from the “Bath Oolite,” so extensively mined and quarried in the vicinity of that city, where the principal strata were first studied by W. Smith. The term was first used by J. d’Omalius d’Halloy in 1843 (Precis Geol.) as a synonym for “Dogger”; but it was limited in 1849 by A. d’Orbigny (Pal. Franc. Jur. i. p. 607). In 1864 Mayer-Eymar (Tabl. Synchron.) used the word “Bathien” = Bajocian + Bathonian (sen. str.). According to English practice, the Bathonian includes the following formations in descending order: Cornbrash, Forest Marble with Bradford Clay, Great or Bath Oolite, Stonesfield Slate and Fullers’ Earth. (The Fullers’ Earth is sometimes regarded as constituting a separate stage, the “Fullonian.”) The “Bathonien” of some French geologists differs from the English Bathonian in that it includes at the base the zone of the ammonite Parkinsonia Parkinsoni, which in England is placed at the summit of the Inferior Oolite. The Bathonian is the equivalent of the upper part of the “Dogger” (Middle Jurassic) of Germany, or to the base of the Upper Brown Jura (substage “E” of Quenstedt).

Rocks of Bathonian age are well developed in Europe: in the N.W. and S.W. oolite limestones are characteristically associated with coral-bearing, crinoidal and other varieties, and with certain beds of clay. In the N. and N.E., Russia, &c., clays, sandstones and ferruginous oolites prevail, some of the last being exploited for iron. They occur also in the extreme north of America and in the Arctic regions, Greenland, Franz Josef Land, &c.; in Africa, Algeria, German East Africa, Madagascar and near the Cape (Enon Beds); in India, Rajputana and Gulf of Cutch, and in South America.

The well-known Caen stone of Normandy and “Hauptrogenstein” of Swabia, as well as the “Eisenkalk” of N.W. Germany, and “Klaus-Schichten” of the Austrian Alps, are of Bathonian age.

For a general account, see A. de Lapparent, Traité de géologie (5th ed., 1906), vol. ii.; see also the article Jurassic.

(J. A. H.)

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