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Arietites Crossi
''Arietites'' is a genus of massive, giant evolute, Psiloceratoidea, psiloceratacean Ammonoidea, ammonites in the family Arietitidae in which Whorl (mollusc), whorls are subquadrate and transversely ribbed and low keels in triplicate, separated by a pair of longitudinal grooves, run along the Dorsal and ventral, venter. Fossils are known world wide from the lower Sinemurian stage of the Early Jurassic, Lower Jurassic. Safari Ltd made an ''Arietites bucklandi'' figurine in 2014. Similar Genus, genera include ''Megarietites'' in which the keels are reduced and ''Epammonites'' in which the ribs are more closely spaced. Species * ''Arietites ablongaris'' * ''Arietites alcinoe'' Reynès, 1879 * ''Arietites anastreptoptychus'' Franz Wähner, 1891 (possibly a synonym of ''Paracaloceras subsalinarium''; Wähner) * ''Arietites bisulcatus'' * ''Arietites bonnardii'' Alcide Dessalines d'Orbigny, 1879 * ''Arietites brookei'' * ''Arietites bucklandi'' George Brettingham Sowerby, 1816 * '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Jurassic
The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic–Jurassic extinction event, 201.3 Ma (million years ago), and ends at the start of the Middle Jurassic 174.7 ±0.8 Ma. Certain rocks of marine origin of this age in Europe are called "Lias Group, Lias" and that name was used for the period, as well, in 19th-century geology. In southern Germany rocks of this age are called Black Jurassic. Origin of the name Lias There are two possible origins for the name Lias: the first reason is it was taken by a geologist from an England, English quarryman's dialect pronunciation of the word "layers"; secondly, sloops from north Cornwall, Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias and Carbonif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
