MAKE A MEME View Large Image The Quarterly journal of the Geological Society of London (13206038635).jpg VON BUCK ON BEAR ISLAND 55 <br> Island although in these islands the characteristic petrifactions are <br> enveloped in sandstone and not in limestone ; and in this ...
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Keywords: The Quarterly journal of the Geological Society of London (13206038635).jpg VON BUCK ON BEAR ISLAND 55 <br> Island although in these islands the characteristic petrifactions are <br> enveloped in sandstone and not in limestone ; and in this manner the <br> Scandinavian peninsula as a centre is enclosed on the northern the <br> eastern and the southern sides ; ” a nucleus round which a whole <br> system of formations are grouped and which has been the seat of <br> mighty revolutions on the surface of the earth That the southern <br> limit of the Productus formation has been advanced so far to the south <br> by the knowledge of the stratification of Bear Island is an important <br> gain to geology for which we are indebted to Keilhau's researches <br> Ventral valve Dorsal valve <br> Spirifer Keilhavii fig 3 belongs to that division of Spirifers <br> the winged Alati in which the hinge-border is not curved and is as <br> wide or even wider than the greatest breadth of the shell ; the sides <br> descend perpendicularly from the ends of the hinge-border and unite <br> with the front by a gentle curve Thick broad ribs Falten cover <br> the shell and only six or eight on each side These ribs are again <br> divided not only once but each rib has usually at most two smaller <br> ones on the sides They are only simple towards the beak These <br> broad divided ribs particularly distinguish this Spirifer from others <br> similar to it In the sinus only the finer ribs are observed and no <br> larger ones The beak is strongly curved over and the area is con- <br> sequently low and itself somewhat arched The ventral valve is only <br> moderately arched indeed far less so than is usual in similar forms ; <br> the dorsal valve rises much higher This dorsal valve is thickly <br> covered with those siliceous groups and rings Kieselsystemen und <br> Kieselringen which are always observed where shells become silicified <br> Here also the silicification takes place below the calcareous shell which <br> is pushed off and destroyed by the siliceous rings <br> This Spirifer is nearly two inches broad and almost as long <br> Length 100; breadth 111; thickness 48; breadth to length of <br> sinus 40 100 <br> The division or dichotomy of the ribs and striae is by no means so <br> characteristic and decisive among Spirifers as among Terebratulse ; 36933286 113687 51125 Page 55 Text v 3 http //www biodiversitylibrary org/page/36933286 1847 Geological Society of London NameFound Productus NameConfirmed Productus NameBankID 4310929 NameFound Spirifer NameConfirmed Spirifer NameBankID 4349330 Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 3 1847 Geology Periodicals Smithsonian Libraries bhl page 36933286 dc identifier http //biodiversitylibrary org/page/36933286 smithsonian libraries Information field Flickr posted date ISOdate 2014-03-17 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/13206038635 2015-08-26 12 51 25 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1847 Photos uploaded from Flickr by Fæ using a script
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