150 THE LIAS AMMONITES. 



In France Harp, opalinum and Lyt. torulosum, which may be regarded as the 

 leading fossils of this zone, have been collected at Vassy, Yonne; at Villenote, near 

 Semur, Cote d'Or; at Salins, Jura; and Besangon, Doubs ; at Amende, Lozere; at 

 Eontenay, Vendee ; and at Charolles, Saone-et-Loire ; and I obtained a number of 

 Ammonites from Milhau, Aveyron; which all belong to the same zone. Diuuortier^ has 

 given a list of several localities in which he has found this zone in the Rhone Valley, and 

 has especially noted la Verpilliere, Isere; where the workings for iron-ore in this region 

 bring the many beautiful fossils of this zone into collectors' hands, as Belemaites exilis, 

 Bel. tricanaliculatus, Bel. Dorsetensis, Bel. pyramidalis. Nautilus lineatus, Har^). 

 opalinum, Harp. Aale?ise, Harp, mactra, Harp, costula. Harp. fluitanSy Harp, sub- 

 insigne, Harp, crassifulcatum, Harp. Briordense, Harp. Allconi, Harp. Lorteti, Harp, 

 fallax, Lyt. hircinum, and Lyt. torulosum, all of which Dumortier refers to the Opalinum- 

 zone. 



The Inferior Oolite and its Ammonite-zones. 



The zone of Harpoceras opalinum is so closely related to that of Harpoceras 

 Murchisonce that I consider a short account of the latter a proper complement to my 

 sketch of the Upper Lias. The affinities and differences between these two formations 

 will then be placed fairly before the student, and the reasons be made evident for my 

 definition of the limits of the Lias formation. 



Leckhampton Hill, near Cheltenham, exhibits one of the most typical sections in 

 Gloucestershire of the three sub-divisions of the Inferior Oolite, where the following beds 

 are admirably exposed : — Eig. 11, Nos. 1, 2, and 3 represent the zone of Cosmoceras Par- 

 kinsoni ; No. 4 the zone of Stephanoceras Humphriesianum ; Nos. 5, 6, and a, b, c, the zone 

 of Harpoceras Murc/iisona ; those rest comformably on d, the Cephalopoda- ov Lurense- 

 bed, which is here very thin ; e, p, g, is the Upper Lias resting on h, the Marlstone. 



No. 1. The Upper Trigonia-hed is a coarse brown ragstone, containing many fossils, 

 chiefly as moulds and impressions of Trigonia costata^ Sow., T. decorata Lye, Lima 

 cardiiformis. Sow., Bhynchonella concinna. Sow., Terebratula spinosa, Schl., Cosmoceras 

 Farhinsoni, Sow., Ecltinohrissus clunicularis, Lhywdd, Holectyjms depressus, Leske, and 

 Clypeus Plotii, Klein ; in thickness it is about seven feet. 



No. 2. The Gryphaa-bed, an ancient oyster-bank, is almost entirely composed of 



Gryphcea sublobata, Desh., accompanied with Plioladomya Heraulti, Agass., Terebratula 



Meriani, 0pp., Taneredia donaciformis. Lye, Gervillia tortuosa, Phil., and many other 



species ; but the dominant shell is the Gryphaa ; this bed is about eight feet in thickness. 



1 'Depots Jurass. du Bassin dii Rhone,' t. iv, p. 237, 1874. 



