GATJLT AND TTPPEK CHALK NEAR FOLKESTONE. 437 



Bed III. (Grey Chalk). 



Consists of a soft, grey, mottled, marly chalk, having a thickness 

 of eight feet; many hard nodules of chalk occur in this horizon. This 

 bed forms the lower portion of Dr. Barrois's " Niveau a Ammonites 

 varians" 



The following fossils may be noted as coming from this band : — 



Discoidea subuculum. 

 Oidaris vesiculosa. 

 Goniaster, sp. 

 Pseudodiadema variolare. 

 Serpula annulata. 

 Rhynchonella Mantelliana. 

 Pecten Beaveri. 

 elongatus. 



Pecten orbicularis. 

 Panopasa, sp. 

 Corax heterodon. 

 Notidanus rnicrodon. 

 Oxyrhina Mantelli. 

 Ammonites yarians. 

 rhotomagensis. 



Bed IV. (Grey Chalk). 



The middle bed of the Ammonite s-rliotomagensis zone is composed of 

 light-grey, banded, marly chalk, about eleven feet in thickness. 

 Eight feet up in this bed three well-marke^ bands occur, each being 

 one foot in thickness. The first band consists of light grey chalk, 

 very hard in texture, and poor in organic remains ; the second, or 

 middle band, consists of dark grey chalk of soft texture, in which 

 many fossils are met with, notably A. rhotomagensis and A. Mantelli. 

 Mr. Griffiths states he has found specimens of the former from this 

 bed weighing as much as a hundredweight. Large specimens of A. 

 leivesiensis also occur here. 



It is worthy of notice that most fossils from this band have the 

 shells well preserved upon them. 



The third band is like the first in composition. 



This bed is placed in the zone of A. varians by Dr. Barrois in his 

 " Assise a Holaster s^<fy/?o&os^«s." 



The following fossils occur : — 



Radiolites Mortoni (rare), in the 



lower 8 feet only. 

 Cidaris vesiculosa. 

 Pseudodiadema variolare. 

 Serpula annulata. 

 — — , a species peculiar to the middle 



dark band. - 

 Pecten Beaveri. 



Bed V. (Grey Chalk). 

 Commonly known as the " cast "-bed, is of a light French-grey 

 colour, mottled and striped with markings of a darker colour, filled 

 with fragments of comminuted shells and a large assemblage of 

 fossils, many of which resemble the Gault fauna. It is particularly 

 rich in Gasteropoda. I am indebted to Mr. J. S. Gardner for the 

 names of several of the species found in this bed. This chalk is 

 tolerably soft, sufficiently so to be capable of being cut with a knife ; 

 therefore the fossils can be readily obtained. It has a thickness of 

 only 2 feet 9 inches ; and through this bed the spout of the Lydden 

 flows. The rise of the marly chalk above the sea-level occurs about 

 a mile and a half to the east of the escarpment of Folkestone Hill ; and 



Pecten elongatus. 



orbicularis. 



Raulinianus ? 



Ammonites Mantelli. 



rhotomagensis. 



lewesiensis. 



varians. 



