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| Keywords: The Quarterly journal of the Geological Society of London (12711762844).jpg 42 <br> PROCEEDINGS OF THE GEOLOGICAL SOCIETY <br> as in JEtheria sometimes wide apart and regular as the septa of an <br> Orthoceras\ the interspaces are occasionally empty but are more <br> usually filled with calcareous spar The whole inner stratum of shell <br> is frequently replaced by crystalline carbonate of lime <br> Figs 2 3 ” Sections q/ Hippurites cornu-vaccinum Bronn <br> Fig 2 Fig 3 <br> Fig 2 Upper lialf of a longitudinal section nat size taken in the direction <br> d b of Fig 3 cutting only the base of the posterior tooth f <br> Fig 3 Transverse section of a larger specimen f nat size at about the level d h <br> of Fig 2 cutting the point of the posterior apophysis a' » and showing <br> the peculiar shell-texture deposited by the anterior adductor a <br> I m n duplicatures ; u umbonal cavity of left valve ; r of right valve ; <br> c c' cartilage-pits ; t f teeth ; a a muscular apophyses ; d outer <br> shell-layer ; e inner sheU-layer <br> A longitudinal section shows the laminae of shell filling up the <br> interior nearly to the summit leaving but a small space for the body <br> of the animal now occupied by hard limestone <br> The upper valve serves as an operculum to close the aperture of <br> the lower valve and does not thicken with age ; its outer stratum is <br> permeated by canals which radiate from the centre to the margin <br> and give off small branches which appear as pores on the outer sur- <br> face The inner layer is always metamorphic and crystalline ; it <br> gives off processes which penetrate to some depth the substance of <br> the lower valve <br> The interior of the lower valve has been figured and described by <br> Goldfuss and D'Orbigny Goldfuss's figure Petr Germ t 164 <br> f 1 c p 300 has been generally overlooked perhaps because he <br> described it merely as an example of Radiolites agariciformis <br> wanting the upper layers <br> The British Museum has lately acquired a specimen precisely similar <br> fig 4 The inner layer exhibits an irregularly cellular structure <br> which I have not met with in any other Hippurite and to which its <br> excellent preservation is probably due The cells are large irregular 35614602 110213 51125 Page 42 Text v 11 http //www biodiversitylibrary org/page/35614602 1855 Geological Society of London NameFound Hippurites NameConfirmed Hippurites EOLID 4773611 NameBankID 4195877 NameFound Orthoceras NameConfirmed Orthoceras EOLID 30106 NameBankID 1861424 NameFound Radiolites agariciformis Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 11 1855 Geology Periodicals Smithsonian Libraries bhl page 35614602 dc identifier http //biodiversitylibrary org/page/35614602 smithsonian libraries Information field Flickr posted date ISOdate 2014-02-23 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/12711762844 2015-08-26 20 54 33 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1855 Photos uploaded from Flickr by Fæ using a script | ||||
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