UPPER AND LOWER CHALK OF DOVER, ETC. 



239 





Dover. 



Cambridge- 

 shire. 



Pollicipes striatus, Darwin 



Eschara (species) 



* 

 



* 



•X- 



..L 



■X- 

 9 



* 

 * 

 * 



Terebratulina ffracilis, Schloth 



striata, Wahl, 



Terebratula semiglobosa, Shy 



Rhynclionella Cuvieri, d^ Orb .. 





limbata, d'Orb 



plicatilis, Sbi/ 



Pecten Beaveri, Sby 



IJima spinosa, Sby 



striata, Sby 



Dutempliana, d'Orb 



Ostrea vesicularis. Lam 



Inoceramus Bronffniarti, Sby 



mytiloides, Mant 



problematicus, d'Orb 



Corax heterodon, Eeuss 



Macropoma 





Zo7ie o/Holaster planus. — The thickness of this zone I give as 

 22 feet. In it the chalk passes into the layers of hard rock already 

 described. Its superior limit is drawn above the uppermost of the 

 two well-marked flint-lines. Many specimens of sponges and Yen- 

 triculites can be seen at this horizon, their form and structure 

 showing as iron-stains ; but other fossils are not numerous. Holaster 

 planus is certainly the distinguishing form ; it was fairly abundant 

 in the upper 10 feet of the zone, though rare in the lower portion 

 of it. Many of my specimens were crushed or broken. The pre- 

 sence of this Echinoderm, unaccompanied by any other fossil of like 

 character or in the same abundance, marks the zone clearly from the 

 over- or underlying one. 



List of Fossils from the 



Spongia, sp. 

 CephaHtes, sp. 

 Guettardia stellata, Nisch. 

 Plocoscypbia couvoluta, T. Smith. 

 Ventriculites. 



Micraster cor-bovis, Forbes. 

 Holaster planus, Mant. 

 Cyphosoma simplex, Forbes, — 

 radiatum, Sorig. 



Vermilia ampullacea, Sby. 



Terebratula semiglobosa, Sby. 



Zone, of Holaster planus. 



Terebratula carnea, Sby. 

 Khynchonella reedensis, Ether. 

 plicatilis, Sby. 



Lima spinosa. 

 Pecten Beaveri ? 



Pleurotomaria perspectiva, Mant. 



Scaphites, sp. 

 Ammonites, sp, 



Ptychodus mammillaris, Ag. 



Polyptycbodon. 



