Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 131 



The line of separation between the Cenomanian and the Greensand 

 is sharply marked, and the lithological difference between the two is 

 striking. The one is a yellowish-grey, slightly glauconitic chalk, 

 the other is a green marly sand in which large grains of glauconite 

 preponderate, and even at the top, which is most calcareous, they 

 give a distinct greenish tint to the deposit. This green sand is so 

 soft that it can be dug with the fingers. 



No fossils of any kind rewarded a search in the Greensand, nor 

 was the base of the Cenomanian very fossiliferous. Many of the 

 cherts and siliceous masses were evidently sponges, too bulky to 

 carry away. 



Most of the section given above is in the zone of Ammonites 

 MantelU ; the highest part of this zone, with the overlying Craie de 

 Rouen, or zone of Ammonites rotomagensis, and the Craie marneuse 

 is seen at the quarry at Lisores, about a mile north-west of the 

 railway-station at Vimoutiers. About 40 feet of fine-grained, glau- 

 conitic, sandy chalk of the upper part of the zone of Ammonites- 

 MantelU was here exposed, with courses of rough lumpy chalk, 

 and cherts, some scattered and some in layers. 



The base of the zone of Ammonites rotomagensis is marked by a 

 bed of intensely hard, creamy-yellow, crystalline, and glauconitic 

 chalk, containing the usual hard siliceous masses of partly-formed 

 chert. A series of small pits showed similar hard beds alternating 

 with layers of soft grey and very glauconitic marly chalk, so soft in 

 places that it could be almost dug with the fingers. These beds 

 were in turn overlain by the Craie marneuse, a whitish-grey, slightly 

 glauconitic, marly chalk not unlike in texture to the top of our own 

 Grey Chalk. 



Thus the whole succession of the Cenomanian seen at Yimoutiers 

 is as follows, the thicknesses given being supplied to us by 

 M. Lecoeur: — 



Feet. 



Turonian. Craie marneuse 10-14 



n f Craie de Rouen or Zone of Ammonites rotomagensis 33 



Cenomanian. j Zone of Ammonites MantelU 113-115 



Upper Greensand 10 



Corallian. ■ 



Many of the fossils found in the Craie de Rouen are in light 

 brown phosphate. We recognize in this Craie de Rouen Beds 7 and 

 8 of the section at Cape La Heve. 



M. Lecoeur, of Yimoutiers, has sent us the following list of fossils 

 collected by him from the Craie de Rouen of that locality and 

 permits us to publish it : — 



Q. J. G. S. No, 206. 



