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On New Ammonites from the English Chalk

Published online by Cambridge University Press:  01 May 2009

L. F. Spath
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Extract

Ammonites are comparatively common in the Cenomanian or Lower Chalk, become rarer in the Turonian or Middle Chalk, and are very scarce in the Upper Chalk. On a former occasion, when pointing out that while ammonites were unknown from the Micraster cor-testudinarium Chalk of England, they occurred in the same Chalk in the north of France, the writer was inclined to attribute this absence or scarcity to limited horizontal distribution of the ammonites. The possibility, however, of there being gaps in the Chalk succession, for example at the horizon of Actinocamax plena, at the Chalk-Rock, in and above the cor-anguinum zone, etc., cannot be denied. The zone of Micraster cor-anguinum is not quite so barren as the zone below, but the only ammonites hitherto known from it are doubtful examples, probably referable to Parapuzosia. One impression, on an oyster, of part of the ventral area of a large specimen, possibly of P. corbarica Grossouvre sp., was collected by Mr. Dibley in the London-Portland Pit at Northfleet, Kent, and Dr. Rowe recorded probably comparable Parapuzosia (“ammonites of the leptophyllus group”) from Dorset and Yorkshire.

Type
Original Articles
Information
Geological Magazine , Volume 63 , Issue 2 , February 1926 , pp. 77 - 83
Copyright
Copyright © Cambridge University Press 1926

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References

page 77 note 1 Spath, in Lang, Spath, and Richardson, “Shales-with-Beef”: Quart. Journ. Geol. Soc., vol. lxxix, 1923, p. 87.Google Scholar

page 78 note 1 “Ammonites de la Craie Supérieure”: Mém. Carte Géol. Dét. France, 1893, p. 174, pi. xxvii, fig. 1.Google Scholar

page 78 note 2 “Zones of the White Chalk”: Proc. Geol. Assoc., vol. xvii, 1901, p. 75.Google Scholar Ibid., vol. xviii, 1904, p. 252.

page 78 note 3 The record of Ammonites (?) pseudogardeni Schlüter, from the cor-anguinum zone (instead of the quadratus zone) of Yorkshire, is obviously due to a slip.

page 78 note 4 Kreidebildungen von Texas, 1852, p. 31, pl. iii, fig. 1 a—c.Google Scholar

page 78 note 5 “Note on the Genus Mortoniceras,” Japanese Journ. Geol. and Geog., vol. ii, No. 2, 1923, pp. 27–30.Google Scholar

page 78 note 6 In Rowe, loc. cit., pt. iv, Yorkshire, 1904, p. 288.Google Scholar

page 79 note 1 Spath, , “Ammonite Horizons of the Gault and Contiguous Deposits”. Summ. of Progress for 1922 (1923), Mem. Geol. Survey, pp. 139–49. Spath, “Monograph of the Ammonoidea of the Gault”: pt. 1, Pal. Soc. vol. for 1921 (1923), p. 4. Spath, “Ammonites of the Speeton Clay and Subdivisions of the Neocomian”: Geol. Mag., Vol. LXI, 1924, pp. 73–89.Google Scholar

page 81 note 1 In addition to those already quoted: “Up. Cret. Amm. from Pondoland”: Ann. Durban Mus., vol. iii, No. 2, 1921, pp. 39–56; “Senon. Amm. Fauna of Pondoland: Trans. Roy. Soc. S. Afr., vol. x, pt. 3, 1922, pp. 113–47; “Cret. Amm. from Angola”: Trans. Roy. Soc. Edinb., vol. liii, pt. 1, No. 6, 1922, pp. 91–160; “Up. Alb. Ammon. from Portug. East Afr. With an Appendix on Up. Cret. Amm. from Maputoland”: Ann. Transvaal Mus., vol. xi, pt. 3, 1925, pp. 179–200.Google Scholar