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I. The Cambrian Rocks of the British Islands, with especial reference to the occurrence of this Formation and its Fossils in Ireland

Published online by Cambridge University Press:  01 May 2009

Wm. Hellier Baily
Wm. Hellier Baily
Affiliation:
Acting Palæontological to the Geological Survey of Ireland.
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Extract

The term Cambrian (from Cambria, the ancient name of Wales) was originally employed by the Rev. Professor Sedgwick to include a great series of fossiliferous and other rocks occurring below the Bala Limestone in North Wales. Sir Charles Lyell adopts to a certain extent this classification, dividing it into Upper and Lower Cambrian.

Type
Original Articles
Information
Geological Magazine , Volume 2 , Issue 15 , September 1865 , pp. 385 - 400
Copyright
Copyright © Cambridge University Press 1865

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References

page 385 note * Manual of Elementry Geology (6th edit), pp. 106, 569, &c.Google Scholar

page 385 note † Siluria (2nd edit.) p. 21, &c.Google Scholar

page 386 note * J.B., Jukes, Student's Manual of Geology (1862), pp. 435, 436.Google Scholar

page 386 note † Siluria (2nd edit)., p. 27.Google Scholar

page 386 note ‡ Ibid., pp. 22, 23.

page 386 note ‖ Quart. Journ. Geol. Soc. of Lond., vol. xii. p. 248 (1856), and vol. xiii. p. 206 (1857).Google Scholar

page 387 note * For a description of the geology of this district, see a memoir by Messrs. Jukes and Haughton, ‘On the Lower Palæozoic Rocks of the South-east of Ireland,’ Trans. Royal Irish Academy, vol. xxiii. p. 563, &c. (1859).Google Scholar

page 387 note † Vide sheets 112 of the one-inch scale, Maps of the Geological Survey of Ireland, and Explanations to sheets 102 and 112 (1861).

page 387 note ‡ Sheets 121 and 130.

page 388 note * This conclusion does not appear to me to be affected by the reputed discovery by the Geological Survey of Canada, as announced by Sir William Logan, the Director, at the last meeting of the British Association, of a fossil named Eozoön Canadense, referred by Dr. Dawson to the group of Foraminifera, and said to be from rocks below the Cambrians, in strata of the Laurentian series (alluded to in former numbers of this Magazine, viz., No. 1, p. 47; No. 5, p. 205 &c.; and No. 7 of vol. ii. p. 3 &c). The specimens exhibited on that occasion I had the opportunity of examining before the meeting; and from that inspection and subsequent observation I feel considerable doubt as to its being an organic structure, and still more as to Eozoön belonging to so high a group as that of the Foraminifera ; for, supposing it could be satisfactorily proved to be a fossil, its alliance would rather seem to have been with the Protozoa, or Sponges. It struck me, however, as being nothing more than a peculiar mechanical condition of the rock; which was a variety of serpentine, a mineral known to be of aqueous origin, and to be for the most part composed of the debris of other rocks; and, from the mode of its deposit, often exhibiting, when polished, wavy or contorted laminae, and having occasionally a vesicular or irregularly cellular appearance, such as these specimens of Canadian Serpentine appeared to me to show.

page 390 note * Vide sheet 121, one-inch scale, Maps of the Geological Survey of Ireland.

page 392 note * Journ. Geol. Soc of Dublin, vol, iii. p. 60 (1844).Google Scholar

page 392 note † Ibid.,, vol. iv, p. 20 (1848).

page 393 note * ‘On Anneloid Tracks in the Rocks of Bray Head,’, Journ. Geol. Soc. Dublin, vol. vii. p. 184, pl. 5, figs. 1–5; and ‘On the Zoological Relations of Bray Head and Howth, with an Account of the Fossils of Irish Cambria,’ Journ. Geol. Soc. Dublin, vol. viii. p. 68, pl. 7, figs. 1, 2.Google Scholar

page 393 note † ‘The Genus Oldhamia, its Characters, &c.,’ Trans. Roy. Irish Academy, vol. xxiii, (1858).Google Scholar

page 394 note * I have noticed similar double markings occurring on some of the fine-grained laminated grits at Carrick Mountain. From the same locality was also procured a large worm-cast resembling those of the Histioderma.—W. H. B.

page 396 note * For excellent figures and description of both these varieties, see Johnston's ‘British Zoophytes,’ pl. 15 and 16, vol. ii. pp. 79, 80 vol. i. pl. 14, figs. 3, and 15 and 16, vol. ii.Google Scholar

page 397 note * British Zoophytes, vol. i. p. 341, and pl. 16, fig. 1.Google Scholar

page 397 note † Treatise on Oldhamia, p. 551.Google Scholar

page 398 note * Journ. Geol. Soc. Dublin, vol. vii. p. 184, pl. 5, figs. 1–5; and Trans. Royal Irish Academy, vol. xxiii. p.56.Google Scholar

page 398 note † Journ. Geol. Soc. Dublin, vol. viii. p. 71.Google Scholar

page 399 note * Journ. Geol. Soc. Dublin, vol. viii. p. 116.Google Scholar