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SPEETON BEDS

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Originally appearing in Volume V25, Page 633 of the 1911 Encyclopedia Britannica.
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SPEETON BEDS , in See also:

English See also:geology, a See also:series of See also:clays well exposed at Speeton, near See also:Filey on the See also:Yorkshire See also:coast. See also:Peculiar See also:interest attaches to these beds for they are the See also:principal representatives in See also:Britain of the marine phase of the See also:Lower Cretaceous See also:system. The Speeton Clays pass downwards without break into the underlying See also:Kimeridgian; they are capped by the Red See also:Chalk, which may be regarded as the See also:equivalent of the Upper See also:Gault of See also:southern See also:England. These beds thus See also:form a passage series between marine See also:Jurassic strata and those belonging undoubtedly to the Cretaceous system; in this way they correspond with the Purbeck-See also:Wealden rocks, which form a connecting See also:link between estuarine Jurassic and Cretaceous strata. Above the dark, bituminous, nodular shales with Kimeridge fossils at the See also:base of the Speeton See also:Clay comes the See also:zone of Belemnites lateralis (34 ft.), with Olcostephanus gravesiformis, 0. rotula, and See also:species of Hoplites and Oxynoticeras; this is followed by the zone of Belemnites jaculum, with B. cristatus, Olcostephanus (Astieria) astieri, O. (Simbirskites) inversus and 0. (S.) Speetonensis in ascending See also:order; Echinospatagus cordiformis, a species found' in the typical Neocomian See also:area, also occurs in this zone. The next higher zone is that of Belemnites brunsvicensis ( = semicanaliculatus) (See also:loo ft.), with B. Speetonensis, Hoplites deshayesii, and Amaltheus bicurvatus. The topmost zone is characterized by Belemnites minima with Inoceramus concentricus and I. sulcatus; it consists of a few feet of mottled clays. It appears, therefore, that while the lower portions of the Speeton Clay are the equivalents of the Wealden and perhaps of the Purbeck beds, the higher portions are the equivalents of the Lower See also:Greensand and See also:part of the Gault. In See also:Lincolnshire the upper Speeton beds are represented by the Carstone and Tealby See also:Lime-See also:stone and Clay, and the lower Speeton by the Claxby Ironstone, Spilsby See also:Sandstone and lower part of the Tealby clay.

A similar faunal See also:

horizon is recognized in See also:Heligoland and See also:Russia. See CRETACEOUS; NEOCOMIAN; KIMERIDGIAN; also G. W. Lamplugh, Q.J.G.S. (1889), xlv. (1896), Hi.; See also:Rep. Brit. Assoc. (189o); A. Pavlow and G. W. Lamplugh, See also:Bull. See also:soc. See also:imp. nat.

See also:

Moscow (1891), and Q.J.G.S, (1897), liii.

End of Article: SPEETON BEDS

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