Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/332

 238 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [March 24, rostris, 0. frons, Park., and JSjJondylus truncatus ; whilst in the south-west and the south these latter beds are separated from the horizon of Inoceramus labiatus by the entire thickness of the Angou- mian, Mornasian, and Provencian stages (which in some places is not less than from 550 to 600 metres, equal to from 1825 to 2000 feet), and therefore by three distinct faunas. Inoceramus labiatus is there accompanied by Ammonites rusticus. Sow., peramplus, Sow., navicularis, Sow., and Woollgari (Mant.), Terebratella carentonensis, &c. The superposition of the two stages is visible on the sides of the plateau on which the town of Angou- leme is built, the cornice of the plateau itself being formed by a thick bed of solid limestone, much used for building-purposes, and abounding in Radiolites lombricalis, D'Orb., and R. (Hijo^urites) cornu-pastoris, Desmoulins. Here we have another new horizon, unknown, or at most only suspected to exist, in the basin of the Loire, and which in its turn bears still more important strata of another solid kind of lime- stone, of which the differential fauna is represented by Hippurites organisans, Desmoul., IT. cornu-vaccinum, Bronn, and Sphcerulites Sauvagesii, D'Homb. With this Hippurite limestone in the south-west and the south of Prance terminates that which I have designated by the name of Craie moye^me, and which, with the sandstone of Uchaux and the limestone with Radiolites lombricalis, separates the beds with Ino- ceramus labiatus from those with Spondylus truncatus, Lamk., Lima Hoperi, Sow., and Micraster laxoporus, D'Orb. The Upper Cretaceous is composed of 4 stages : — 1st. Sandstones and sandy limestones, with Rhynchonella Bau- ^asii, D'Orb, 2nd. Marly glauconite limestone, with Ostrea auricularis (Biongn.) {Gryphcp.a), 0. frons (Park.), 0. santonensis, D'Orb., Spondylus trun- catus, Lamk. [Podopsis), Micraster cor-testudinarium, Agassiz, and cor-anguinumy Radiolites Jissicostatus, D'Orb., and Sphcerulites Oo- quandi. 3rd. White chalky limestone, with Ostrea vesicularis, Lamk., 0. larva, Lamk., 0, laciniata, D'Orb., Ananchytes ovatus, Sphcerulites Hoeninghausii, Desml., Radiolites crateriformis, Desml., and He- mipneustes radiatus, corresponding with the chalk of Meudon and the Upper Chalk, and forming the hills round Cognac, which produce the best brandy in the world. 4th. Solid yellow limestone in the Department of the Dordogne, with Faujasia Faujasii, D'Orb., Hippurites radiosus, Desml., Sphceru- lites cylindracea^ Desml., and Radiolites ingens and Bournoni, D'Orb., corresponding with the highest portion of the Maestricht Chalk. In the explanatory text of the Geological Map of the Charente which I have prepared *, I have divided the Cretaceous formation of the south-west in the following manner, beginning from the Gar- donian stage, with which it commences (see fig. 1) : —
 * Coquand, Deseript. Geol. et Pal. de la Charente, vol. i. 1858.