Geological Society of London. 223 



ontological differences between the Cretaceous rocks of that country 

 and those of the Anglo-Parisian basin being so great as to lead at 

 first sight to the impression that they belonged to two different 

 formations. The author arrived at the following classification and 

 nomenclature of the divisions of the Cretaceous rocks, the palaeonto- 

 logical characters and geographical range of which were described 

 in the paper : — 



I. — Upper Cretaceous. 



A. Red Lacustrine Sandstone of Vitrolles (= Garumnien of Leymerie). 



B. Dordonien. 



C. Campanien {= Upper Chalk. 



D. Santonien (= Superior Lower Chalk). 



E. Coniacien (Sandstone), 



II. — Middle Cretaceous. 



F. Provencien. 



G. Mornasien. 

 H. Angoumien. 



I. Ligerian (^ Inferior Lower Chalk). 



J. Carentonien. 



K. Gardonien. 



L. Rhothomagien (= Upper Greensand and Chalk-marl). 



M. Gault. 



III. — Lower Cretaceous. 

 N. Aptien. 

 1. Upper. 



I Lower!' } = ^°^^^ Greensand. 

 0. Neocomien. 

 P. Valengien. 



Discussion. — Mr. J. W. Flower called attention to the great discrepancy between 

 the thickness of the Cretaceous beds in France and those in England. This was 

 principally made up by several strata entirely wanting in England, and for the 

 most part of a totally different character, being either of freshwater origin, 

 or else Hippurite limestone. Another great feature of distinction was the pre- 

 sence of coal-bearing beds with numerous layers of lignites. That these 

 beds were of Cretaceous origin was proved by their occurrence under undoubted 

 Eocene beds. Among the fossils of the Algerian Chalk were those of several genera 

 unknown in the Cretaceous beds of England. 



Dr. Duncan suggested that possibly the tipper Coal-beds might be the equivalent 

 of those of Aix la Chapelle. He doubted whether any decided synchronism in strata, 

 spread over so extensive an area as that of the Cretaceous deposits, could be estab- 

 lished by the mere occurrence of certain fossils in them ; nor could he attach much 

 value to supposed specific difierences in shells of such character as Osfrea. The 

 variations in condition in the sea-bottom would lead to variations in the Testacea, 

 and there were signs to be found of great variations going on before the form 

 of Hippurites was developed. He regarded Hippurites as a modified form of Chama 

 or Caprina, and thought it was parasitic on coral reefs in the same way as its modern 

 representative. He accounted for its presence by the great development of corals at 

 that period in the Cretaceous seas. 



Mr. Judd remarked upon the repeated changes which had occurred in the opinions 

 of foreign geologists as to the limits of the various " stages " into which the Creta- 

 ceous rocks might be divided, and indicated that this of itself was equivalent to the 

 abandonment of the principles laid down by D'Orbigny. He further observed that in 

 the recent changes, even as evidenced by M. Coquand's paper, there was a tendency 

 to approach the views as to the classification of the Cretaceous beds established by 

 the late Professor Edward Forbes, and generally accepted by English geologists. 



Professor Morris observed that the object of the French geologists had been to 

 remove the opinion that mere mineralogical characters were sufficient to distinguish 

 Cretaceous strata. He called attention to the existence of copper and antimony in 

 some of the Lower Cretaceous beds, and to the great break that appeared to exist 

 between the Lower and Middle Cretaceous series. Another curious point was that in 

 the South of France there appeared to be passage-beds between the Upper Cretaceous 

 and Eocene beds. 



