JURASSIC OF THE PARIS J3ASIN. 



549 



if only the development in each country could be correlated respec- 

 tively with these. 



The cliffs of Auberville are mainly composed of fossiliferous Oxford 

 Clay (known as Argile de Dives); and Caumonts section, in which he 

 indicates the presence of Coral Rag, Upper Calcareous Grit, and Kim- 

 meridge Clay beneath the Cretaceous rocks, is quite deceptive. Hebert, 

 however, gives details of 33 beds seen in the central portion of the cliff, 

 all referred by him to the Middle Oxfordian. His lower 19 divisions, 

 comprising 195 feet of clays, with various bands of nodules, would 

 correspond to the Weymouth Oxford Clay. To within 60 feet of the 

 top this is pure clay, and bands towards the base are very fossiliferous, 

 the horizon being indicated by such fossils as Amm. Lamberti, A. 

 arduennensis, Turbo Meriani, Modiola imbricata, Nucida ornata, and 

 Rliynclionella varians. These are succeeded by numerous bands of 

 ferruginous oolite, scattered in the midst of the clays through a 

 thickness of about 20 feet, after which the clay still continues for 

 another 40 feet. The whole of these have Ostrea dilatata in great 

 abundance. One might be tempted to regard the ferruginous bands 

 as corresponding to the JSTothe grits ; but the latter are better 

 represented by the mass which succeeds the Oxford Clay. This 

 commences with a bed of oolitic grit of about 5 feet, then more 

 clay for 5 feet, and then 12 feet of strong ferruginous oolite and 

 grit, which is marly in parts, and has a lumachelle of small oysters 

 at the top. These beds are very constant : they may be traced 

 all along the cliff of Auberville as far as Villers, and may be seen 

 again at low tide on the shore east of Trouville. At this last 

 locality the lower beds contain Ammonites plicatilis ? and Pecten 

 Jibrosus. The intervening clays make no show ; and the upper part 

 are dark-brown oolitic grits, exactly similar to those at Osmington, 

 crowded with large Gervillia aviculoides, Trigonia perlata, and 

 Pecten Jibrosus ; towards the top is a bed of Serpula tricarinata, 

 and, finally, a regular Trigonia-bed like the lower one at Osmington. 

 These are the beds Nos. 20-29 of Hebert's Auberville section, and 

 Kos. 2 and 3 of his Trouville section, which is rather differently 

 described. The principal fossils noticed, besides those mentioned, 

 were Astarte ovalis, Cerithium muricatum?, Unicardium globosum, 

 Pleuromya tellina, and Exogyra spiralis. The next portion of the 

 series corresponds to the Nothe clays. It consists at Auberville of 

 blue clay at the base with hard bands and fossils, and at the top of 

 purple unfossiliferous clay, making a total of 6-8 feet. At Trouville 

 the base is darker, and contains lumachelles of Exogyra nana. There 

 is a hard blue calc-grit with fucoidal marks at the top, which, from its 

 position, may be taken as the representative of the Bencliff calc-grit. 

 These are Nos. 30-32 of Hebert's Auberville section, and apparently 

 No. 3 of his Trouville section, though the grit is not noticed. Above 

 these come about 6 feet of alternations of clays and ferruginous oolitic 

 bands at Trouville, scarcely recognizable at Auberville, in which 

 Exogyra nana and Pecten Jibrosus are still abundant, with Trigonia 

 corallina, Pecten lens, Lucina Moreana, and Pseudodiadema sp. 

 These must be reckoned with the succeeding beds, which are perfect 



