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The graptolite biostratigraphy of a Llandovery outlier near Llanystumdwy, Gwynedd, North Wales

Published online by Cambridge University Press:  01 May 2009

S. J. Baker
S. J. Baker
Affiliation:
Department of Earth Sciences, Downing Street, Cambridge CB2 3EQ
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Summary

Llandovery strata at Llanystumdwy are described. Ninety graptolite species have been identified enabling the establishment of the following zones: acinaces, cyphus, triangulatus, magnus, leptotheca, convolutus, ?sedgwickii, turriculatus and crispus. The name Llanystumdwy Mudstone Formation is proposed for previously undescribed mudstones cropping out on the River Dwyfor at Llanystumdwy and includes all strata referable to the acinaces to turriculatus zones. Comparison is made between Llanystumdwy and other areas, notably Northern England and Southern Scotland

Type
Articles
Information
Geological Magazine , Volume 118 , Issue 4 , July 1981 , pp. 355 - 365
Copyright
Copyright © Cambridge University Press 1981

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