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II.—On some Life Zones in the Lower Palæozoic Rocks of the British Areas, as defined mainly by Researches During the Past 30 Years

Published online by Cambridge University Press:  01 May 2009

Henry Hicks
Affiliation:
Middle Cambrian

Extract

From the foregoing remarks it will be seen that the Middle Cambrian, as at present defined, is characterized by having numerous Life Zones in which, usually, species of the genus Paradoxides, or of some closely allied forms, may be considered the dominant organisms. Up to the present the genus Olenellus, so typical of the Lower Cambrian rocks, has not been foundindirect association with Paradoxides, but some of the associated genera are equally characteristic both of the Lower and of the Middle Cambrian.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1894

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References

page 442 note 1 Etheridge, R., fil., Records Geol. Surv. New South Wales, vol. i. pt. 3, 1889 (1890), pp. 172179, pl. xxix.Google Scholar

page 442 note 2 Mr. G. F. Matthew, who has worked out the zones in the Cambrian rocks of New Brunswick, Canada, with much care and success, has recently described a new genus, Protolenus, which, he says, is there the characteristic iossil ot the Olenellus zone (“Pre-Paradoxides beds”). With it is associated the genus Ellipsocephalus, which occurs in Europe in the Paradoxides beds, as well as in those containing Olenellus (see Canadian Record of Science, October, 1892).

page 443 note 1 Mr. Walcott, C. D.,inhis most instructive monograph “The Fauna of the Lower Cambrian or Olenellus Zone”, says, at p. 594, “The cause of the abrupt change from the Olenellus to the Paradoxides fauna is not yet fully recognised. While a considerable portion of the genera pass up, very few of the species are known to do so, and in none of the sections has there been found a commingling of the characteristic species of the Lower and Middle Cambrian”.Google Scholar

page 443 note 2 Quart. Journ. Geol. Soc. vol. xxviii. p. 173.Google Scholar

page 444 note 1 Quart. Journ. Geol. Soc. 11, 1865.Google Scholar

page 444 note 2 “The Physical conditions under which the Cambrian and Lower Silurian rocks were probably deposited over the European areas” (Q.J.G.S. vol. xxxi. p. 552).Google Scholar

page 445 note 1 See also the Presidential Address to the Geological Society 1881.

page 446 note 1 GEOL. MAG. Vol. IV. p. 294.Google Scholar

page 446 note 2 Ibid. p. 493.

page 446 note 3 Quart. Journ. Geol. Soc. vol. xxxiii. p. 652.Google Scholar

page 447 note 1 GEM,. MAG. Dec. II. Vol. IX. p. 565.Google Scholar

page 447 note 2 Quart. Journ. Geol. Soc. vol. xli. p. 476.Google Scholar

page 447 note 3 “Catalogue of the Collection of Cambrian and Silurian Fossils contained in the Geological Museum of the University of Cambridge”, 1873, p. 15.