Siluria : a history of the oldest rocks in the British Isles and other countries with sketches of the origin and distribution of native gold, the general succession of geological formations, and changes of the earth's surface / by Sir Roderick Impey Murchison.
- Roderick Murchison, 1st Baronet
- Date:
- 1867
Licence: Public Domain Mark
Credit: Siluria : a history of the oldest rocks in the British Isles and other countries with sketches of the origin and distribution of native gold, the general succession of geological formations, and changes of the earth's surface / by Sir Roderick Impey Murchison. Source: Wellcome Collection.
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![EOZOON OF THE LAUEENTIAN EOCKS. way the same foundation-stones exist, and have their proper place far beneath the well-known Silurian formations of Sweden and Norway. The figures of Eozoon Canadense, which arc here given, have been se- lected by my friend Professor Eupert Jones from the works of Piincipal Dawson and Dr. Carpenter. fj- Fossils (1). 1. Portion of the serpentinous marble of Canada, composed of Eozoon; of the natural size. The broken black lines represent the serpentine, and the white spaces are the cal- careous skeleton. Copied from Dr. Dawson’s nature-printed section of a s])ecimen of Eozoon Canadense (from Petite Nation Seigniory), first polislied and then corroded with acid. [See Canadian Naturalist and Geologist, Ajiril, IStih.] 2. The serpentinous portion of a piece of Eozoon, after maceration in acid, magnified. It presents the natural casts of the chambers and tubes, or a model of the sarcode of the Eozoon. (After Dr. Carpenter’s plate in tlie Intellectual Obseryer, No. XL. p. 3(K) Ac.) 3. A portion of the chamber-walls, or calcareous shell, of the Eozoon, restored and highly magnified, showing the tubuliferous walls, the pseudopodial tufts in the inter- mediate skeleton, and the stolon-passages. (After Carpenter, loc. cit.) As these authors, who have long studied this class of animals, arc supported by Eeuss and other sound foreign naturalists in their belief that the Eozoon (of which two nominal species have been described) is truly a Foraminifer, I how to their decision, and regard the Laurentian as the base of all Palseozoic deposits. Whilst the Laurentian gneiss of Scotland differs essentially (as I have shown in other publications*) from the superjacent ciystalline rocks (gneiss in parts) of Lower Silurian age, the most marked distinction, besides its infraposition, consists in the entire divergence of its direction or strike, and its abrupt separation from all the overlying formations. Thus, whilst * For many complat? demonstrations of the infraposition, in the Western Highlands and the Hebrides,of the Laurentian gneiss to theCambrian sandstones and conglomerates, and of the latter to Silurian rocks (the latter being often highly crys- talline, gneissose, and micaceous), see the memoir by Mr. Geikie and m3’self. Quart. Jotirn. Geol. Soc. May 1861 vol. ivii. p. 171 &c. See Chap. VIII.](https://iiif.wellcomecollection.org/image/b28094360_0043.jp2/full/800%2C/0/default.jpg)
