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PENDLESIDE SERIES

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Originally appearing in Volume V21, Page 87 of the 1911 Encyclopedia Britannica.
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PENDLESIDE SERIES, in geology, a series of shales between the upper division of the Carboniferous Limestone and the Millstone Grits occurring in the Midlands between Stoke-on-Trent and Settle. It consists of black limestones at the base, followed by black shales with calcareous nodules, which pass into sandy shales with ganister-like sandstones. In places the series attains a thickness of 15oo—r000 ft., and where it is thickest the Millstone Grits also attain their maximum thickness. The peculiarities of the series, which is characterized by a rich fauna with Productus giganteus, P. striatus, Dibunophyllum, Cyathaxonia cornu and Lonsdaleia floriformis, can be best studied on the western slope of Pendle Hill, Lancashire, in the valley of the Hodder, dividing the counties of Lancashire and Yorkshire, at Mam Tor and the Edale valley in Derbyshire, and Morredge, the Dane valley in north Staffordshire, Bagillt and Teilia in North Wales, and Scarlett and Poolvash, Isle of Man. The limestones at the base are hard, compact and fissile, often cherty, and vary much in the amount of calcium carbonate which they contain, at times passing into calcareous shales. These limestones and shales contain a distinct fauna which appears for the first time in the Midlands, characterized by Pterinopecten papyraceus, Posidoniella laevis, Posidonomya Becheri, Posidonomya membranacea, Nomismoceras rotiforme and Glyphioceras striatus. Immediately below beds with this fauna are thin limestones with Prolecanites compressus, Stroboceras bisulcatus, many trilobites, and corals referable to the genera Cyathaxonia, Zaphrentis and Amplexizaphrentis. The fauna characteristic of the Carboniferous Limestone becomes largely extinct and is replaced by a shale fauna, but the oncoming of the age of Goniatites is shown by the presence in the upper part of the Carboniferous Limestone of numerous species and genera of this group, Glyphioceras crenestria being the most common and having the wider horizontal range. The whole Pendleside series can be divided into zones by the different species of Goniatites. At the base Prolecanites compressus characterizes the passage beds between the Carboniferous Limestone and the Pendlesides; Nomismoceras rotiforme and Glyphioceras striatus are found in a narrow zone immediately above. Then Glyphioceras reticulatum appears and reaches its maximum, and is succeeded by Glyphioceras diadema and Glyphioceras spirale, while immediately below the Millstone Grits Glyphioceras bilingue appears and passes up in that series. The Millstone Grits are characterized by the presence of Gastrioceras Listeri. The Pendleside series is therefore characterized by an Upper Carboniferous fauna, Pterinopecten papyraceus, Posidoniella laevis and some other species which pass up right through the Coal Measures appearing for the first time, and the base of the series rnarks the division between Upper and Lower Carboniferous times. The series passes eastward into Belgium and thence into Germany, when the same fossil zones are found in the basin of Namur and the valley of the Dill. Traced westward the series is well developed in Co. Dublin and on the west coast of Cos. Clare and Limerick. There can be no doubt that the Pendleside series of the Midlands represents the Lower Culm of Codden Hill, north Devon, and the Lower Culm of the continent of Europe. The faunas in these localities have the same biological succession as in the midlands. See Wheelton Hind and J. Allen Howe, Quart. Journ. Geog. Soc. vol. lvii. (1901), and numerous other papers by the first-named author. . (W. H1.)
End of Article: PENDLESIDE SERIES
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