GAULT AND UPPER CHALK NEAR FOLKESTONE. 439 



Bed VI. (Grey Chalk). 



The base of this bed is found immediately resting upon the " cast- 

 bed." It is about 148 feet in thickness ; the lower portion of it for 

 about 10 feet is slightly lighter in colour than the chalk of the cast- 

 bed, but becomes very much lighter higher up, where it assumes a 

 very light j-ellowish grey colour ; and within a few feet of the top the 

 chalk is of soft texture. 



This bed is not so fossiliferous as the " cast-bed." The first 93 feet 

 above it is very poor in organic remains, and is the " Craie argileuse 

 avec bancs durs a Ammonites rhotomagensis ;" and the upper 55 feet 

 of this bed is the zone of Belemnites plenus of Dr. Barrois. Discoidea 

 cylindrical and Holaster subglobosus are peculiar to this bed ; in con- 

 sequence of the latter being very characteristic and plentiful in it, I 

 propose to call it the zone of Holaster subglobosus. 



The palates of Ptychodus poly gyrus and P. decurrens are met with 

 towards the top of this zone of a darker colour than those coming 

 from bed IX. of the Lower Chalk. 



The nodules of iron pyrites occurring in this bed are round and 

 rusty brown in appearance, never bright. 



The following are the fossils met with in the bed : — 



Cidaris vesiculosa. Pecten elongatus. 



Holaster subglobosus (common only in 



this bed). 

 Discoidea cylindrica (only in this bed). 

 Pseudodiadema variolare. 

 Goniaster mosaicus (plentiful,). 

 Ophiura ? 



Euoploclytia sussexiensis. 

 Hoploparia, claws of. 

 Pecten Beaveri. 



orbicularis. 



Janira qoinquecostatus. 

 Plicatula sigillina. 



pectinoides. 



Ptychodus decurrens. 



polygyrus. 



Fish-remains. 

 Ammonites, sp. 

 Tiirrilites costatus. 



Bed VII. (Grey Chalk). 



This bed is very well marked, and forms a contrast to the beds 

 above and below, and consists of a yellowish gritty white chalk. 

 In this particular section it is about 4 feet in thickness, and forms 

 the junction between the grey and white chalk. 



It is usually termed the Belemnites-zone, on account of the fre- 

 quency of Belemnites plenus in this horizon. This bed is about 170 

 feet above the mean sea-level. Mr. \Vhitaker, in the ' Survey Me- 

 moir,' vol. iv. p. 33, says, speaking of this bed, " Where it rises west 

 of Shakespere's Cliff its separation from bed VI. is not well marked ; 

 but further west it is clear, the white being separated from the grey 

 by some very thin yellowish bands. 



This bed forms the upper portion of what M. Hebert and Dr. 

 Barrois, in the Pas de Calais, consider the zone of Belemnites plenus, 

 which fossil is met with very frequently in this bed ; but an elongated 

 form of it occurs in the upper portion of the bed below. 



Dr. Barrois * considers that Belemnites plenus lived at the end of 



* 'La zone a Belemnites picnics,' par C. Barrois. Lille: 1875. 



Q. J. G. S. No. 131. 2 g 



