Abstract
THIS table will be welcome to students and teachers, for the existing charts are now quite out of date. To compile such is a laborious and somewhat thankless task, for it is impossible to please every one; indeed, the authors admit that in two respects, retaining the Permian in the Palæozoic and placing the Wealden in the Jurassic, they “seek to assert general rather than individual opinion.” As to the former, the question seems to be largely one of locality; but in the latter we should have preferred the conservative side, at any rate till better cause is shown for the change; especially since it has led to the virtual suppression of the Neocomian as a system. For the same reason we are glad to see the Tremadoc group left in the Cambrian system. The latter they allow to be an important geological system, though we should have liked to see the alternative title, “Primordial Silurian,” entirely suppressed, for it is commemorative of nothing less than an unwarrantable usurpation. The authors include the Solva Beds of St. Davids with the Menevian, which no doubt is justified by the presence of Paradoxides; but in that case too small a thickness is assigned to the system, for this addition would make it at St. Davids over two thousand feet. Remembering its importance on the Continent, we should have ventured to exalt Rhætic, thin as it may be in Britain, to the dignity of a system, and we think that over much importance is conceded to the subdivisions of the Tertiary series. Are the Thanet Sands or the Oldhaven Beds—not to mention others—more important than the Lower Calcareous Grit or the Stonesfield Slate? Yet we find the former among Formations and the latter in Subdivisions. Does not the statement that the glacial deposits contain only derived fossils beg a disputed question? It would be well to add “slates” to the economic products of Charnwood, for the “honestone,” which is mentioned, is very local. A notable feature is the recognition as formation of Torridonian, Uriconian, Dalradian and Lewisian in the Archæan rocks, though some objection may be taken to the third name, on the ground that as originally defined it was a much too heterogeneous assemblage, and we may doubt whether the Moine schists, having regard to their history, form a good type. These criticisms, however, affect only points of detail, and some may even regard them as excellences, while as to the general excellence of the table and its high value to students there cannot be the slightest question.
The Table of British Strata.
By Dr. H. Woodward Mr. H. B. Woodward. (London: Dulau and Co., 1901.)
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The Table of British Strata . Nature 63, 560 (1901). https://doi.org/10.1038/063560a0
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DOI: https://doi.org/10.1038/063560a0