158 



I. — The Lias. 



M. Maetin divides the Lias into four stages — 1st, Hettangien 

 on Infra- Lias. 2nd, Sinemurien ou Lias inferieur. 3rd, Liasien 

 ou Lias moyen. 4th, Toarcien ou Lias snperieur. 



/ Calcaire mameux a Ammonites angulatua, 

 __ T-r . 1 • T J T • 1 et Ammonites liasicus. 



The Hettangien ou Infra-Lias LumacheUes a Ammo7iites planorbis, A. 



\ tortilis, et A. Burgundice. 



The Luniachelles, zone a Ammonites Burgundice, Mart., evidently 

 represent the beds I have described as the zone of Ammonites 

 planorbis, which rests upon the Saurian beds with Ostrea liassicaj 

 in the sections I have given in my memoir on "the Avicula 

 contorta and Lower Lias of the south of England."* M. Martin's 

 Ammonites are almost identical with forms of A. planorbis and 

 A. tortilis, collected from beds of the same horizon in England, 

 in the localities given in that memoir. Associated with the 

 Ammonites are one or two species of Hemipedina, nearly allied 

 to the small Urchins, collected from this zone near Pinhay Bay, 

 Dorsetshire, and the Guinea Bed at Binton, Warwickshire. 

 Corals, hkewise, are found in the Lumachelles, nearly allied to 

 the species of Septastrcea, Isastrcea, Stylastrcea, and Montlivaltia, 

 discovered in this and the next zone in England. The general 

 facies of the fauna cannot be mistaken, for similar forms of the 

 same genera appear for the first time in these basement beds 

 of the Lias formation, many of them identical with, and 

 when different from, nearly allied to the common type. 



*' Calcaire mameux & Ammonites angidatus et Am. liasicus; un 

 des horizons paleontologiques les mieux caracterses qu'il y ait 

 dans le Departement de la Cote-d'Or, et les plus riches en 

 fossiles varies, est certainement la zone a Ammonites Moreanus. 

 Limite a deux ou trois metres de puissance au maximum, ce 

 depot parait correspondre a une periode d'animalization d'lme 

 admirable fecondite. C'est au sein de ses assises qu'a ete 

 recuiUie la charmante faune que nous avons signalee, I'an 

 dernier, et qui a de si intimes rapports avec la faune hettangienne, 

 dont on doit la connaissance aux travaux de M. O. TEEQTJEM.f 



* Quarterly Journal of the Geological Society. Vol. xvi., p. 389 : 1860. 

 t Paleontologie stratigr. de I'lnfra-lias, p. 38 : 1860. 



