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| Keywords: The Quarterly journal of the Geological Society of London (12736136875).jpg THE BORROWDALE SERIES AND THE CONISTON FLAGS <br> 465 <br> hard grey or bluish grey cleaved and often highly calcareous <br> shales containing numerous nodules or thin but distinct bands of <br> limestone In some places the beds of limestone are the most <br> largely developed ; and in other places the shales predominate ; but <br> the two elements of the group are usually intermixed and alternate <br> with one another indefinitely At some localities again as at Ash <br> Gill near Torver and at the head of Appletreeworth Beck the shales <br> are largely developed at the expense of the limestone and are suffi- <br> ciently thick to have been extensively worked for slates At Keisley <br> near Dufton again the series is almost calcareous and the shales <br> appear to be entirely confined to its upper portion Finally at <br> Beck and Waterblain near Millom the group consists of an upper <br> series of cleaved fossiliferous shales in the lower part of which a <br> great thickness of limestone is developed dis continuously in the <br> form of great lenticular masses of a purely calcareous nature <br> In its intimate characters the limestone of the Coniston Limestone <br> group differs greatly in different localities Usually it presents <br> itself as a hard compact greyish blue grey or nearly black lime- <br> stone which in thin sections prepared for the microscope exhibits <br> a subgranular matrix in which fragments of Crinoids Corals or <br> Brachiopods are imbedded at intervals At Keisley fig 2 where <br> we have most carefully examined it three principal varieties may be <br> distinguished ” 1 a hard compact greyish blue limestone with the <br> microscopic characters and general aspect of the ordinary variety of <br> the limestone just alluded to ; 2 a reddish or pink compact marble <br> with numerous patches of white calcite both portions of the mass <br> appearing in microscopic sections to be crowded with minute organ- <br> isms and fragments of larger fossils ; 3 a light- coloured whitish <br> blue or white coarsely crystalline limestone which is seen in thin <br> sections to be composed of innumerable fragmentary organic remains <br> and microzoa ; imbedded in transparent calcite and having large <br> crystals of calc-spar with their characteristic cleavage-lines shooting <br> through the mass in various directions <br> Fig 2 ” Sketch Section of the Coniston Limestone at Keisley near <br> Dufton Length rather more than one third of a mile <br> Fault <br> Jsi' N W <br> Keisley <br> High-Cup- Pennine <br> Gill Beck Fault <br> S S B <br> a Borrowdale series b Coniston Limestone <br> c Barren ground occupied in whole or in part by the Graptolitic <br> mudstones <br> d Knock beds pale slates p Permian strata 35818616 110705 51125 Page 465 Text 33 http //www biodiversitylibrary org/page/35818616 1877 Geological Society of London Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 33 1877 Geology Periodicals Smithsonian Libraries bhl page 35818616 dc identifier http //biodiversitylibrary org/page/35818616 smithsonian libraries Information field Flickr posted date ISOdate 2014-02-24 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/12736136875 2015-08-26 20 03 38 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1877 Photos uploaded from Flickr by Fæ using a script | ||||
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