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The glaciations of Wales and adjacent areas [Introduction / by Colin A. Lewis; Chapter 8: The upper Wye and Usk regions / by Colin A. Lewis and G.S.P. Thomas]

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[From the preface]: The landscapes of Wales and adjacent areas have been profoundly influenced by glaciation. Much attention has been paid to the origins of the Welsh landscape, and, especially, to its morphology. This book, like its predecessor, "The glaciations of Wales and adjoining regions", published in 1970, aims to encourage and guide further research into the glacial history of Wales and its borderlands. [From Chapter 8]: Mid-Wales was probably glaciated on at least two occasions during the Pleistocene. The glacial sediments and landforms discussed in this chapter appear to be of Late Devensian age. The scale of glaciation during the Late Devensian varied from ice-sheet to cirque glacier in size. During glaciation the mid-Wales ice-sheet shrank to become two major valley glaciers, those of the Wye and the Usk. The age of deglaciation, especially in the Wye drainage basin, is a matter for debate and much absolute dating is still needed.

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