A. W. A. Rushton, 2000. "Southern England and subsurface", A revised correlation of Ordovician Rocks in the British Isles, R. A. Fortey, D. A. T. Harpe, J. K. Ingham, A. W Owen, M. A. Parkes, A. W. A. Rushton, N. H. Woodcock
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To the east of the Welsh Borderland the Ordovician is exposed only in a few scattered outcrops, but it has a wide subsurface distribution, being known from many boreholes. The outcrops all appear along the Malvern lineament and the structural features at the edges of the Warwickshire and South Staffordshire coalfields, and, apart from the Lickey Hills inlier, are all known to be of Tremadoc age. Although all the Tremadoc rocks show general similarity to the Shineton Shale Formation, they have been described under several local names, as shown in Fig. 16. The succession in the Tortworth Inlier (Column 38) is from Curtis (1968), the age of the Micklewood Beds being revised by Fortey & Owens (1992). The Bronsil Shales of the Malvern Hills (Column 39) have yielded Cressagian fossils including Rhabdinopora fabelliformis socialis and the trilobite Boeckaspis mobergi (Worssam et al. 1989, p.6). The Lickey Quartzite SW of Birmingham (Column 40) was formerly attributed (with doubt) to the Cambrian and the Barnt Green Volcanic Formation to the Precambrian (Cowie et al. 1972), but Molyneux (in Old et al. 1991, p.4) showed that these divisions are post-Cambrian and probably Ordovician in age. The Merevale Shale Formation of the Nuneaton and Dosthill Inliers (Column 41) overlie the Merioneth Series conformably and have yielded Rhabdinopora fabelliformis socialis from a horizon some 90 m above its base (Taylor & Rushton 1972, p.35), but the Merioneth-Tremadoc boundary is not closely constrained in the area (Bridge et al. 1998, p. 36).
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This Report is revised and expanded from the 1972 publication providing an up-to-the-minute account of the British Ordovician formations and their correlation nationally and internationally. It also includes the most comprehensive treatment of Ireland ever attempted. The reference list of a comprehensive bibliography of papers on the subject published since 1970.
The British sections are the type for the Ordovician System and classical in stratigraphical, tectonic and volcanic studies. The Charts bring together 30 years of research over the period in which plate tectonics has revolutionized our understanding of the Lower Palaeozoic rocks of the British Isles.
This Special Report will be a valuable reference for research and applied geoscientists working with rocks of Ordovician age. It will be of particular interest to those working in, or visiting, the Welsh mountains and the English Lake District.