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VI.—On the Original form of Sedimentary Deposits1

Published online by Cambridge University Press:  01 May 2009

Extract

We may now examine how far these theoretical conclusions explain and are confirmed by what is seen in nature. First we know that in most formations there are great masses of what is now, or must have been once, fine-grained sediment. These often make up the bulk of the formation. We may quote the Ordovician, Silurian, and Devonian slates, the Keuper, Lias, Oxford and Kimmeridge Clays, the G-ault and London Clay; but we can give no such list of thick masses of marine sandstone. Fine sediment, therefore, has, as a matter of fact, made thicker masses of rock than coarse sediment; but this could not be the case if deposits thinned out seawards, where the fine sediment is carried. Again, it is impossible to imagine a thickness of a thousand feet and more constantly occupying a position near the shore; there is no room for it. If you depress the land, you remove the shore.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1903

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Footnotes

1

A paper read at the Meeting of the British Association, Belfast, September, 1902.

References

page 73 note 1 U.S. Geol. Survey Ann. Eep., vol. xii, p. 563.

page 73 note 2 Q.J.G.S., vol. xxxviii, p. 513.

page 73 note 3 Q.J.G.S., vol. xxxviii, p. 513.

page 74 note 1 Q.J.G.S., vol. lvi, pp. 69–135.

page 74 note 2 Q.J.G.S., vol. xxxvii, pp. 141–150.

page 74 note 3 Q.J.G.S., vol. xvi, p. 80.

page 75 note 1 Hull: op. cit., p. 8.

page 75 note 2 Godwin-Austen: Q.J.G.S., vol. xii, p. 64.

page 75 note 3 Since this paper was read at Belfast, I have received the 21st Annual Report of the U.S. Geol. Survey, with an account of the Cretaceous formation of Texas by R. T. Hill. A full account is therein given of the thickening seaward of the Glen Rose formation (see pp. 138–9 and 369–382). This has been preserved from denudation by the overlying Fredericksburg Division, and is bounded below by the Palaeozoic rocks. Its thickening is observed in artesian wells. It has thus retained its original form, which is ‘wedge-shaped,’ but the termination seaward I cannot find described.

page 75 note 4 Q.J.G.S., vol. vi, p. 79.

page 76 note 1 Q.J.G.S., vol. vi, p. 86.

page 76 note 2 GEOL. MAG., 1899, Dec. IV, Vol. VI, Pl III.

page 78 note 1 J. G. Buchanan: Scottish Geogr. Mag., vol. iii, p. 222.