Vol. 52.] 



A DELIMITATION OF THE CENOMANIAN. 



105 



Chalk. 



Upper 

 Greensand. 



following section was taken by one of us in 1880 from the slipped 

 mass at Collins Point, near Ventnor :— 



Feet, 

 f 6. Chalk Marl with scattered glauconitic grains near the 



j base, Ammonites varians and Pecten Beaveri 5 



1 5. Greenish-buff glauconitic marl full of fossils and phos- 



I phatic nodules, Ammonites varians, etc 3£ 



^4. Compact, dark green, sandy marl, with quartz and 



glauconite, but few fossils or phosphatic nodules 2£ 



3. A layer enclosing lumps of calcareous sandstone partially 

 phosphatized, irregular pieces of dark phosphate and 



•{ broken Pecten asper about 0| 



2. Yellowish-green sand mottled with darker green ; yields 



Pecten orbicularis, Ostrea vesiculosa, and Pecten asper. 2 

 1. Continuous layer of dark-grey cherty stone with compact 

 ^ green sand below, seen for 5 



The material of 2 passes into that of 4 between the lumps of 

 phosphatized stone in 3. At Niton 3 and 4 form a kind of boulder- 

 bed full of such lumps, with phosphatized sponges, Cardiaster fossarius, 

 Pecten asper, Terebratella pectita, and other fossils, but without any 

 Ammonites. The Chloritic Marl (5), on the other hand, might be 

 called a ' Cephalopoda Bed,' so abundant are ammonites of the 

 species varians, Coupei, and Mantelli, with Turrilites tuberculatus 

 and Morrisii. It is also characterized by the remarkable siliceous 

 sponge Stauronema Carteri (Sollas), which has not yet been found 

 below this horizon, nor far above it. 



As one of us spent a week in 1880 for the purpose of examining 

 these beds at the base of the Chalk, and afterwards engaged the 

 services of Mr. M. Norman, of Yentnor, in collecting carefully from 

 them, it seems desirable to give the list of fossils then obtained, 

 in order to show the difference of the faunas. In this list the 

 numbers above the columns indicate the beds as numbered in the 

 section just described : — 





2. 



3, 4. 



5. 



Porifera (Sponges). 

 Halirrhoa aqariciformis (phosphatized) 



* 



* 



* 



* 

 * 



* 

 * 



* 



* 

 * 



Plocoscyphia labrosa, Smith (phosphatized) ... 

 Jerea Websteri 





Stauronema Carteri, Sollas 



ACTINOZOA. 



Micrabacia coronula, Goldf. 



Echinodermata and Annelida. 

 Cardiaster fossarhis, Benett 



Discoidea subiccula, Leske 



Hemiaster Morrisii, Forbes 



Holaster Icevis, var. carinatus 



Serpula, sp 



Vermicularia umbonata, Sow 





