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A Shelly Band in Graptolitic Shales

Published online by Cambridge University Press:  01 May 2009

John Challinor
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Extract

In the midst of a typically graptolitic development of the Valentian Series in Wales, a thin band containing a variety of shelly fossils has recently been noticed. It occurs in the Rheidol Gorge, Cardiganshire; part of the region described by Professor O. T. Jones in 1909 (1); the locality being that referred to by him as “F. 15”, and the stratigraphical position 6 feet below the layer of calcareous nodules defining the top of the “Triangulatus-var.-band”; the shale band “2” in the table showing the beds of the zone of Monograptus communis as developed in the Rheidol Gorge (1, p.488). Professor Jones refers to the presence of “fragments of Orthoceras or Conularia” at this locality. The band has an available outcrop of about 10 feet in length, and it was possible to examine it for some 2 or 3 feet in the direction of dip. It is about 3 inches thick and is not individualized in any way other than by its fossil contents; lithologically it is to all appearances the same as the rest of the dark-blue iron-stained shales in which it occurs.

Type
Original Articles
Information
Geological Magazine , Volume 65 , Issue 8 , August 1928 , pp. 364 - 368
Copyright
Copyright © Cambridge University Press 1928

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References

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