JURASSIC OF THE PARIS BASIN. 



505 



true English Coral Hag, the specimens at the top not being in situ — 

 and also that there is an apparent absence or great rarity of Cidaris 

 Jlorigemma, the spines which occur being either smooth or belonging 

 to C. Smiihii. At the base the most abundant fossil is a large 

 Natica like N. millepunctata, Buv., but perhaps N. grandis ; while 

 the topmost beds are crowded with silicined Nerinceoe, N. sequana 

 bring the most abundant. Other noteworthy fossils are rarer ex- 

 amples of Dicer as arietinum?, Cardium corallinum, Cerithium limce- 

 forme, Pteroceras oceani (undistinguishable from those at Boulogne), 

 Lima oequilatera, Buv., and L. omata, the Modiola imbricata, Rom. 

 (non Sow.), and Terebratida. MM. Sauvage and Buvignier mention 

 also among others Area joectinata, Pecten articulatus, and Chemnitzia 

 heddingtonensis. These characters taken together appear to indicate 

 a higher horizon than the '•Jlorigemma ' Rag, namely one which in 

 spite of its abundant corals should be paialleled with Supracoralline 

 beds elsewhere, or the upper part of theCorallian series when that has 

 been divided as it has been in the Mouse. The upward succession 

 is not well seen in this neighbourhood, the great limestones passing 

 to large-grained oolites with undistinguishable fossils, and then to 

 more compact limestones referred to the Astartian. 



The interpretation of the rocks seen in this district may now be 

 checked by an examination of the country about 20 miles distant to 

 the south. Starting from the town of Beaumont, and going westward, 

 after passing over the Lower Oolites, the Kelloway liock and the 

 Oxford Clay, which is here well developed in an argillaceous form, 

 one comes, at the base of the escarpment of Stonne, to the same sandy 

 nodular beds with Rhynchonella Thurmanni and Perna quadrata as at 

 Neuvizy, duly followed on the top of the hill by the Ferruginous Oolite ; 

 but the bed with Trigonia spinifera was not observed. Above this, 

 on the road to Ochsee, a village three miles south, the succession 

 is perfectly observable on the rough cart-road mounting a barren 

 hill ; at the base are the Lower Calcareous Grit and the Ferruginous 

 Oolite ; near the summit are the great cavitary limestones of Novion, 

 where the Calamophyllice have been, and above them flaggy Oolites 

 &c. full oiNerincece ; but in the intervening space there is no sign of 

 clay, all is calcareous. This portion, however, contains abundant 

 Thaninastraean corals ; and with them Cidaris Jlorigemma was easily 

 found associated with Hemicidaris cremdaris, Cerithium muricatum, 

 and Littorina muricata ; but the Nerincece and Naticai of the limestone 

 above are absent. It thus appears that we are justified in regarding 

 the Novion limestone as Supracoralline ; while al] that can represent 

 the series so well developed in England between the Lower and the 

 Upper Calcareous Grit is the Ferruginous Oolite and the Rag Lime- 

 stone. The upper portions of the series have not been examined 

 in the Ardennes department, as the description given by the before- 

 named authors indicated that they were similar to those to be seen 

 in the northern part of the Meuse. 



2. The Meuse Department. — On entering this we come under the 

 guidance of Buvignier alone (13), whose classical work is well known. 

 He gives the following classification. 



