. The ancient life-history of the earth; a comprehensive outline of the principles and leading facts of palaeontological science. Paleontology. THE JURASSIC PERIOD. 237. eating Sea-snails, such as the Limpets {Patellidoe), the Nerites (Nerita), the Turritellce, Chemfiitzice, &c., still hold a predomi- nant place. The two most noticeable genera of this group are Cerithhwi and Neriftcea — the former of these attaining great importance in the Tertiary and Recent seas, whilst the latter (fig. 169) is highly characteristic of the Jurassic series, though not exclusively confined to it. One of th
. The ancient life-history of the earth; a comprehensive outline of the principles and leading facts of palaeontological science. Paleontology. THE JURASSIC PERIOD. 237. eating Sea-snails, such as the Limpets {Patellidoe), the Nerites (Nerita), the Turritellce, Chemfiitzice, &c., still hold a predomi- nant place. The two most noticeable genera of this group are Cerithhwi and Neriftcea — the former of these attaining great importance in the Tertiary and Recent seas, whilst the latter (fig. 169) is highly characteristic of the Jurassic series, though not exclusively confined to it. One of the limestones of the Jura, believed to be of the age of the Coral-rag (Middle Oolite) of Bri- tain, abounds to such an extent in the turreted shells of Neriiiaa as to have gained the name of " Calcaire a ; In addition to forms such as the preceding, we now for the first time meet, in any force, with the Carnivorous Univalves, in which the mouth of the shell is notched or produced into a canal, giving rise to the technical name of " siphonostomatous," applied to the shell. Some of the carnivorous forms belong to extinct types, such as the Purpuroidea of the Great Oo- hte; but others are referable to well-known existmg genera. Thus we meet here with species of the familiar groups of the Whelks {Buccimim), the Spindle - shells {Fusus), the Spider- shells (Fkroceras), Murex, Rostellaria^ and others which are not at present knov/n to occur in any earlier formation. Amongst the Wing-shells {Fteropodd), it is sufiEicient to mark the final appearance in the Lias of the ancient genus Conularia. Lastly, the order of the Cephalopoda, in both its Tetrabran- chiate and Dibranchiate sections, undergoes a vast devel- opment in the Jurassic period. The old and comparatively simple genus Nautilus is still well represented, one species being very similar to the living Pearly Nautilus {N. pompilius)\ but the Orthocerata and Goniatites of the Trias have finally disapp
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Keywords: ., bookcentur, bookdecade1870, booksubjectpaleontology, bookyear1876
