Hostname: page-component-848d4c4894-mwx4w Total loading time: 0 Render date: 2024-06-17T04:44:53.952Z Has data issue: false hasContentIssue false
  • English
  • Français

The Unconformity between the Millstone Grit and the Carboniferous Limestone at Ifton, Mon.

Published online by Cambridge University Press:  01 May 2009

E. E. L. Dixon
Get access Rights & Permissions [Opens in a new window]

Extract

The object of the present communication is to place on record a section, apparently unique, in which the unconformity between the Millstone Grit and Carboniferous Limestone that exists in parts of South Wales and Monmouthshire is clearly displayed. The exposure was first examined at the suggestion of the brilliant worker who threw so much light on Lower Carboniferous problems, the late Dr. Vaughan. The writer had explained1 the attenuation of the Carboniferous Limestone Series in the Newport (Mon.) district as due to unconformable overstep by the Millstone Grit, similar to an overstep at this horizon that had already been observed near Haverfordwest, at the other end of the South Wales basin, by Professor O. T. Jones.1 The value of the Ifton section in demonstrating that this overstep was widespread was recognized, and photographs, two of which are here reproduced, were secured by H.M. Geological Survey. Since then the unconformity at the eastern end of the South Wales coalfield has been confirmed by the detailed examination of a large area by Mr. F. Dixey and Dr. T. F. Sibly,2 and has been found by the writer, in the course of work not yet published, to reach its greatest known extent in the Abergavenny district. Nevertheless, it seems desirable to describe the Ifton section because it is the clearest exposure known, in the whole of the South-West Province, of the unconformity between the Carboniferous Limestone and the Millstone Grit, and also on account of the remarkable inter-relations of the two formations which it reveals.

Type
Original Articles
Information
Geological Magazine , Volume 58 , Issue 4 , April 1921 , pp. 157 - 164
Copyright
Copyright © Cambridge University Press 1921

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

page 157 note 1 In “The Country around Newport” (Mem. Geol. Surv.), ed. 2, 1909, p. 20.Google Scholar

page 158 note 1 In“The Country around Haverfordwest” (Mem. Geol. Surv.), 1914, p. 151.Google Scholar

page 158 note 2 Quart. Journ. Geol. Soc., vol. lxxiii, 1918, p. 111.Google Scholar

page 158 note 3 Quart. Journ. Geol. Soc., vol. lxi, 1905, pp. 251–2.Google Scholar

page 158 note 4 Geol. Mag., 1912, p. 417; GEOL. MAG., 1918, p. 25.Google Scholar

page 158 note 5 Dixon, E., “The Country around Pembroke and Tenby” (Mem. Geol. Surv.), 1921, chap. x.Google Scholar

page 158 note 6 Quart. Journ. Geol. Soc., vol. lxix, 1913, pp. 272, 275.Google Scholar

page 159 note 1 In the Geol. Surv. Coll. at Jermyn Street Museum (Regd. No. E.D. 1791).

page 163 note 1 Sibly, T. F., Geol. Mag., 1912, p. 420.Google Scholar

page 163 note 2 Geol. Mag., 1918, p. 26.Google Scholar

page 163 note 3 Charles, Richardson, Proc. Bristol Nat. Soc., ser. III, vol. v, 1887, p. 49, section.Google Scholar

page 164 note 1 Charles, Richardson, op. cit.Google Scholar

page 164 note 2 Jones, E. D., Proc. Geol. Assoc., vol. vii, 1881–1882, p. 339.Google Scholar