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II.—On the Occurrence of a New Fossiliferous Horizon in the Ordovician Series of the Lake-District

Published online by Cambridge University Press:  01 May 2009

H. Alleyne Nicholson  and
John E. Marr
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Extract

Below the “Coniston Limestone Series”—if we include under this general title not only the Coniston Limestone proper, but also the “Style End Grassing Beds” of Long Sleddale and the “Dufton Shales” of the Cross Fell area—no fossiliferous beds have hitherto been detected in the Lake—district till the horizon of the Upper Skiddaw Slates (Llanvirn Series) is reached. Between these two horizons are placed the thick and varied volcanic rocks which have usually been grouped together under the name of the “ Borrowdale Series ” (the “ Green Slates and Porphyries ” of Prof. Sedgwick); though it may be taken as certain that this name covers more than one series of volcanic ejecta. Up to the present time, no strata containing fossils have been detected in connection with any of the rooks which have been included under the general title of the “ Borrowdale Series.”

Type
Original Articles
Information
Geological Magazine , Volume 4 , Issue 8 , August 1887 , pp. 339 - 344
Copyright
Copyright © Cambridge University Press 1887

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References

1 From a remark made by MrWard, (Quart. Journ. Geol. Soc. vol. xxxii. p. 24)Google Scholar, we should be disposed to infer that this observer regarded the peculiar characters of these beds as due to extreme weathering. Mr. Teall has beeu good enough to examine for us a specimen of one of the felsitic bands associated with these light-coloured breccias, and informs us that it exhibits porplryritic quartz and felspar in a cryptocrystalline ground-mass. Assuming it to be a lava, he would consider it to be a slightly altered liparite.