ARIETITES STELLARIS. 295 



which belongs to the zone of A. obtustis, have been figured by Sowerby under the name 

 of A. Smithi. 



In Robin Hood's Bay, on the Yorkshire coast, I have found this species, which, 

 however, is very rare in that county, A. stellaris being here the dominant form, and 

 mis-called A. obtusus in most of the public and private collections. 



On the continent of Europe it has been found in France, in the environs of Avallon 

 (Yonne) ; Saint-Ramber (Ain) ; and in the province of Luxemburg, at Ethe ; and it is 

 found in South Germany in many localities. Professor Quenstedt regarded this species 

 as A. Turneri, Sow., and figured it as such ; in pi. iii, fig. 19, of his ' Cephalopoden ' my 

 learned friend recognised the stratigraphical importance of this form, as he found it 

 characteristic of a zone, which he called the " Turnerithone " in his valuable ' Flozgebirge 

 Wiirtembergs.' It is found at Balingen, Ober-Dingen, Betzgingen, and Betzenrieth. 



Arietites stellaris, Soicerbi/. PI. XXII, figs. 1 — 6. 



Ammonites stellaris, Sowerby. Mineral Conchology, vol. i, p. 211, pi. 93, 1815. 



— — De Harm. Mon. Ammon. et Gon., p. 109, 1825. 



— — Guidoni. Journal de Geologie (Boue), iii, p. 276, 1831. 



— — d'Orbigny. Paleontologie Fran9aise, Terr. Jurassique, t. i, 



p. 193, pi. xlv, 1842. 



— — Pilla. Bull. Soc. Geol. de France, ser. ii, t. iv, p. 1063, 1847. 



— TuBNEEi, Quenstedt. Die Cephalopoden, p. 261, 1846 — 9. 



— STELLAEis, Schafhdutl. Von Leonhard und Bronn's Jahrbuch, p. 139, 



1848. 



— — Savi e Meneghini. Geologia della Toscaua, p. 104, 1851. 



— OBTUSUS, Ehrlich. Geognostich. der Nordostlicb. Alpen, p. 22, 1852. 



— STELLAKis, von Hauer. Jahrbuch der k. k. geolog. Keicbsanstalt, iv, p. 



747, 1853. 



— — Chapids et Dewalque. Foss. terr. second. Luxembourg, p. 41, 



pi. V, fig. 2, 1853. 



— — Merian. Verhand. der Natur. Gesellschaft. Basel, p. 77, 1854. 



— — von Hauer. Die Cephalopoden aus dem Lias, Nord-Alpen, 



p. 22, pi. V, figs. 1—3, 1856. 



— — Oppel. Juraformation, p. 82, 1856. 



— — Quenstedt. Der Jura, p. 96, pi. xii, fig. 1, 1858. 



— — Bumortier. Depots Jurass. du Bassin du Rhone t. ii, p. 123, 



1867. 

 Akietites — Tate ^ Blake. Yorkshire Lias, p. 287, 1876. 



Diagnosis. — Shell discoidal, compressed ; whorls four, exposed, one third involute ; 

 sides flattened, covered with thirty ribs, nearly straight on the sides, and bent toward 



