159 



From this zone M. Maktin has collected a total of 176 

 species, of which 68 species are found in the underlying stages, 

 98 species are special to the zone, and 47 pass upwards into the 

 overlying calcaire a Gryphites arquees, or Am. Buchlandi beds. 

 Among the faunaenumerated are 1 Ichthyosaurus, 1 Ichthyodorulite, 

 10 sp. of Cephalopoda, 63 Gasteropoda, 77 Conchifera, 5 Brach- 

 iopoda, 4 Echinodermata, 10 Anthozoa, 3 Annelida and debris of 

 Crustacea. 



This zone is found in Gloucestershire with a limited fauna; 

 in the Harbury cutting of the Great Western Eailway, 

 Warwickshire; and in the coast section near Lyme Regis, 

 with a numerous fauna. It is found, likewise, in the north of 

 Ireland, and in the remarkable Lias district near Portrush. 

 The Ammonites that characterize this zone have been figured 

 and described by M. d'ORBiGNT, under the names Am. Moreanus, 

 Am. catenatus, and Am. Charmassei, which are all so many different 

 varieties of ^m. angulatus, Schloth.; the typical forms of these 

 are collected from the English beds, together with a very rich 

 fauna of small Gasteropoda and Conchifera, many of which are 

 identical with those so beautifully figured by M. Martin, from 

 the zone in the Cote-d'Or, and by MM. O. Teeqtjem et Ed. 

 PiETTE au Lias inferieur de I'est de la France from strata of 

 the same age. 



It is clear, therefore, from this analysis, that the Hettangien 

 ou Infra-Lias of M. Martin consists of the two lowest stages 

 of the true Lias, namely, the "zone of Ammonites angulatus" 

 and the "zone of Ammonites planorhis," the latter resting upon 

 the Gres et Marnes a Avicula contorta and Bone-bed; in all their 

 essential phases these two stages being the true equivalents of 

 the bed so well known by these names to the members of the 

 Cotteswold Club. 



11. SiNEMXJEIEN OTJ LlAS InFERIETIR 



Consists of — a. Calcaire mameux bleuatre a Am. oxynotiis. Am. 

 stellaris, Am. Birchii, &c. b. Marnes et calcaire mameux a 

 Ammon. hisulcatus, cal. mameux a Am. Scipionianus, et Am. 

 rotiform-is. 



N 



