Geological Society, London, Memoirs
Geological Society, London, Memoirs; 1973; v. 7;
p. 3;
DOI: 10.1144/GSL.MEM.1973.007.01.01
© 1973 Geological Society of London
Part I Introduction
The map with the accompanying short memoir represents a notable addition to British geological literature. Professor Wills has compiled from many sources and with many consultants a map showing the surface of England and Wales as it existed in early Permian times, itself a remarkable achievement. In doing this he has developed to a novel degree concepts of the history of erosion surfaces and of the sub-Permian/Mesozoic massifs which are of major importance in considering the structural history of the region. He has suggested that in the English and Welsh highland areas Permian and later erosion modified only slightly much older surfaces, quoting relics of pre-existing peneplains extending back into the Palaeozoic times which were only a short distance below the postulated sub-Permian surface. Thus he lists pre-Upper Coal Measures in North Wales, pre-Lower Carboniferous in North Wales and the Lake District, pre-Late Devonian from Shropshire across into southeastern England and pre-Llandovery in the Welsh borderland.
This is a major extension of previous concepts (for example the view that Wales represented either a dissected Jurassic or late Tertiary surface), but a close analogy is available in east-central England. There (as Wills has shown) the Mesozoic sequence becomes progressively more defective southeastwards on to the London platform, whilst the unconformities at the bases of the individual transgressive units converge at very low angles towards the Thames Valley. Finally there is no distinction between surfaces developed mainly during the Jurassic and the sub-Albian surface. This Mesozoic history had its earlier precursor, for
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This 250-word extract was created in the absence of an abstract.
