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The lithostratigraphical correlation of the uppermost Rhaetic and lowermost Liassic strata of the W Somerset and Glamorgan areas

Published online by Cambridge University Press:  01 May 2009

A. Whittaker
A. Whittaker
Affiliation:
Institute of Geological Sciences, Hoopern House, 101 Pennsylvania Road, Exeter
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Summary

Richardson's (1911) detailed correlations of the Upper Rhaetic and Lower Lias strata of W Somerset are in need of revision; he wrongly identified the basal Langport Bed as the Cotham Marble at Blue Anchor and Lilstock. Likewise, his correlations of the Upper Rhaetic and Lower Lias strata between W Somerset and Glamorgan are erroneous; the lower parts of his Glamorgan Langport Beds were equated with the upper part of his W Somerset Cotham Beds. The greater part of the W Somerset Watchet Beds are, in the hand specimen, lithologically similar to Liassic shales and not to the White Lias ‘marly’ beds of Lavernock as he stated. The matter is important because the W Somerset coast is the recommended type area for the base of the Jurassic System, and Richardson&s classification of the strata is taken as the starting point for fixing this horizon.

Type
Articles
Information
Geological Magazine , Volume 115 , Issue 1 , January 1978 , pp. 63 - 67
Copyright
Copyright © Cambridge University Press 1978

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References

Bristow, H. W. & Etheridge, R. 1873. Vertical sections of the Lower Lias and Rhaetic or Penarth Beds of Glamorgan, Somerset and Gloucester-shires. Geol. Surv.U.K. Vertical Sections 47.Google Scholar
Donovan, D. T. 1956. The Blue Lias of the Bristol district. Proc. Geol. Ass. 66, 182–212.CrossRefGoogle Scholar
George, T. N. et al. 1969. Recommendations on stratigraphical usage. Proc. geol. Soc. Lond. no. 1656, pp.139–66.Google Scholar
Ivimey-Cook, H. C. 1974. The Permian and Triassic deposits of Wales. In The Upper Palaeozoic and Post Palaeozoic Rocks of Wales (ed.Owen, T. R.). University of Wales Press.Google Scholar
Lang, W. D. 1924. The Blue Lias of the Devon and Dorset Coasts. Proc. Geol. Ass. 35, 169–85.CrossRefGoogle Scholar
Orbell, G. 1973. Palynology of the British Rhaeto-Liassic. Bull. geol. Surv. Gt Br. 44, 1–39.Google Scholar
Richardson, L. 1905. The Rhaetic and contiguous deposits of Glamorganshire. Q. JI geol. Soc. Lond. 61,385–424.CrossRefGoogle Scholar
Richardson, L. 1911. The Rhaetic and contiguous deposits of West, Mid and part of east Somerset. Q. JI geol. Soc. Lond. 67, 1–74.CrossRefGoogle Scholar
Warrington, G. 1974. Studies in the palynological biostratigraphy of the British Trias. 1. Reference sections in west Lancashire and north Somerset. Rev. Palaeobot. Palynol. 17, 133–47.CrossRefGoogle Scholar