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The Denbigh Grits; Wenlock Greywackes in Wales

Published online by Cambridge University Press:  01 May 2009

W. A. Cummins
W. A. Cummins
Affiliation:
Department of Geology, The University, Nottingham.
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Abstract

The petrography of the greywackes is described, with special emphasis on rock and mineral grains indicative of provenance. Sedimentary structures are discussed, and current directions based on flute cast measurements are recorded. The stratigraphy and palaeontology of the Denbigh Grits, and the facies of other parts of the Wenlock in the Welsh area are also considered. It is concluded that the greywackes were derived from an area of Pre-Cambrian rocks near south-west Wales and that they were transported along the axes of subsiding troughs by turbidity currents.

Type
Articles
Information
Geological Magazine , Volume 94 , Issue 6 , December 1957 , pp. 433 - 451
Copyright
Copyright © Cambridge University Press 1957

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References

REFERENCES

Bailey, E. B., 1930. New light on Sedimentation and Tectonics. Geol. Mag., lxvii, 77–92.Google Scholar
Battey, M. H., 1955. Alkali Metasomatism and the Petrology of some Keratophyres. Geol. Mag., xcii, 104–126.Google Scholar
Bonney, T. G., 1879. Notes on the Microscopic Structure of some Shropshire Rocks. Quart. Journ. Geol. Soc., xxxv, 662–9.Google Scholar
Boswell, P. G. H., 1949. The Middle Silurian Rocks of North Wales. London.Google Scholar
Bucher, W. H., 1919. On Ripples and Related Sedimentary Surface Forms and their Palaeogeographic Interpretation. Amer. Journ. Sci., cxcvii, 149–210, 241–269.Google Scholar
Clarke, J. M., 1918. Strand and undertow markings of Upper Devonian time as indications of the prevailing climate. Bull. N.Y. State Mus., cxcvi, 199–238.Google Scholar
Cox, A. H., 1915. The Geology of the District between Abereiddy and Abercastle, Pembrokeshire. Quart. Journ. Geol. Soc., lxxi, 273–340.Google Scholar
Crowell, J. C., 1955. Directional current structures from the Prealpine flysch, Switzerland. Bull. Geol. Soc. Amer., lxvi, 1351–1384.Google Scholar
Cummins, W. A., 1957. Some sedimentary structures from the Lower Keuper Sandstones. Liv. Manch. Geol. Journ. (In press.)Google Scholar
Dzulynski, St., and Radomski, A., 1955. Origin of groove casts in the light of Turbidity Current hypothesis. Act. Geol. Pol., 5, 47–66.Google Scholar
Elles, G. L., 1909. The Relation of the Ordovician and Silurian rocks of Conway, North Wales. Quart. Journ. Geol. Soc., lxv, 169–192.Google Scholar
Exner, C., 1949. Tektonik, Feldspatausbildungen und deren gegenseitige Beziehungen in den ostlichen Hohen Tauern. Min. Pet. Mitt., fol. xxx, 1, 197–284.Google Scholar
Greenly, E., 1919. The Geology of Anglesey. Mem. Geol. Survey Gt. Brit.Google Scholar
Hicks, H., 1881. On the discovery of some remains of plants at the base of the Denbighshire Grits, near Corwen, N. Wales. Quart. Journ. Geol. Soc., xxxvii, 482–495.Google Scholar
Hicks, H., 1882. Additional Notes on the Land Plants from the Pen-y-Glog slate quarry near Corwen, North Wales. Quart. Journ. Geol. Soc., xxxviii, 97–101.Google Scholar
Jones, O. T., 1938. On the Evolution of a geosyncline. Quart. Journ. Geol. Soc., lx–cx.Google Scholar
Jones, O. T., 1955. The Geological Evolution of Wales and the Adjacent Regions. Quart. Journ. Geol. Soc., cxi, 323–351.Google Scholar
Kindle, E. M., 1917. Recent and fossil ripple mark. Can. Geol. Survey, Mus. Bull. 25.Google Scholar
King, W. B. R., 1928. The Geology of the District around Meifod, Montgomeryshire. Quart. Journ. Geol. Soc., lxxxiv, 671–700.Google Scholar
Kuenen, Ph. H., 1953. Significant features of Graded Bedding. Bull. Amer. Assoc. Pet. Geol., xxxvii, 1044–1066.Google Scholar
Kuenen, Ph. H., 1957. Longitudinal filling of oblong sedimentary basins. Ver. Kon. Ned. Geol-Mijn, Gen., 189–195.Google Scholar
Kuenen, Ph. H., and Migliorini, C. I.. 1950. Turbidity Currents as a cause of Graded Bedding. Journ. Geol., lvii, 91–127.Google Scholar
Menard, H. W., and Ludwick, J. C., 1951. Application of Hydraulics to the study of Marine Turbidity Currents. Soc. Econ. Pal. Min., Spec., Publ., 2, 2–13.Google Scholar
Niggli, P., 1954. Rocks and Mineral Deposits. San Francisco.Google Scholar
Pettijohn, F. J., 1949. Sedimentary Rocks. New York.Google Scholar
Prentice, J. E., 1956. The interpretation of flow-marking and load casts. Geol. Mag., xciii 393–400.CrossRefGoogle Scholar
Ramsay, A. C., 1866. The Geology of North Wales. Mem. Geol. Survey Gt. Brit.Google Scholar
Rich, J. L., 1950. Flow markings, groovings, and intrastratal crumplings as criteria for the recognition of slope deposits, with illustrations from Silurian rocks of Wales. Bull. Amer. Assoc. Pet. Geol., xxxiv, 717–741.Google Scholar
Roberts, R. O., 1929. The Geology of the district around Abbey-Cwmhir, Radnorshire. Quart. Journ. Geol. Soc., lxxxv, 651–675.Google Scholar
Rucklin, H., 1938. Stromungs-Marken im Unteren Muschel. Kalk des Saarlandes. Senckenbergiana, xx, 94–114.Google Scholar
Shrock, R. R., 1948. Sequence in layered rocks. New York.Google Scholar
Thomas, H. H., 1911. The Skomer Volcanic Series, Pembrokeshire. Quart. Journ. Geol. Soc., lxvii, 175–212.Google Scholar
Thomas, H. H., 1918. Notes on thin sections in Garwood, E. J., and Goodyear, E., On the geology of the Old Radnor District with special reference to an Algal Development of the Woolhope Limestone. Quart. Journ. Geol. Soc., lxxiv, 1–29.Google Scholar
Thomas, H. H., and Jones, O. T., 1912. On the Pre-Cambrian and Cambrian rocks of Brawdy, Haycastle, and Brimaston, Pembrokeshire. Quart. Journ. Geol. Soc., lxviii, 374–400.CrossRefGoogle Scholar
Wallis, F. S., 1927. The Old Red Sandstone of the Bristol District. Quart. Journ. Geol. Soc., lxxxiii, 760–787.Google Scholar
West, R. G., and Donner, J. J., 1956. The Glaciations of East Anglia and the East Midlands: A differentiation based on stone-orientation measurements of the tills. Quart. Journ. Geol. Soc., cxii, 69–87.Google Scholar
Williams, D., 1930. The Geology of the country between Nant Peris and Nant Ffrancon, Snowdonia. Quart. Journ. Geol. Soc., lxxxvi, 191–230.Google Scholar
Williams, H., 1927. The Geology of Snowdon, North Wales. Quart. Journ. Geol. Soc., lxxxiii, 346–427.Google Scholar
Wills, L. J., and Smith, B., 1922. The Lower Palaeozoic rocks of the Llangollen District, with special reference to the Tectonics. Quart. Journ. Geol. Soc., lxxviii, 176–223.Google Scholar
Wood, E. M. R., 1906. The Tarannon Series of Tarannon. Quart. Journ. Geol. Soc., 644–699.Google Scholar