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The stratigraphical relationships of the earliest monograptidae, and the dimorphograptidae

Published online by Cambridge University Press:  01 May 2009

P. Toghill
Affiliation:
Department of Palaeontology, British Museum(Natural History), Cromwell Road, London, S.W.7.

Summary

The earliest monograptids are shown to appear at exactly the same time (base of the vesiculosus Zone in Scotland) as Dimorphograptus and Rhaphidograptus, and the earliest species of these two genera are those with long uniserial portions, the forms wiht shorter uniserial portions appearing in the overlying cyphus Zone. Akidograptus is entirely restricted to the premonograptid beds. One of the earliest monograptids is described as Monograptus cyphus var. praematurus var. nov., which has a distinct and earlier range than M. cyphus s.s. Lapworth.

Type
Articles
Copyright
Copyright © Cambridge University Press 1968

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References

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