UPPEK AND LOWER CHALK OF DOVEE, ETC. 



237 



greater. The name may well be applied to the " Grit Bed " of 

 Mr. Price, the basal 12 feet of which is certainly whiter than the 

 hard yellowish nodular rock which forms the next 20 feet. The 

 whole appears to be the equivalent of those beds of whitish and 

 yellow rock which compose the Melhourn BocJc along the line of 

 country described in the paper referred to above. 



It is true that in the Midlands this rock is only some 10 or 11 feet 

 thick, while its equivalent at Dover is 32 feet ; but as the whole of 

 the zone of EliynclioneUa Cuvieri consists of hard chalk, the fact that 

 a larger part of it should consist of hard nodular rock in one place 

 than in another is not surprising. 



Cardiaster pyrjmcms^ by which Mr. Price distinguishes this zone, is 

 not uncommon ; but it appears to me that Rliynclionella Cuvieri, the 

 fossil selected by the authors of the " Geology of the JS^eighbourhood 

 of Cambridge," is to be preferred, because it is found abundantly at 

 this horizon both here and in Cambridgeshire and Hertfordshire, 

 where, as yet, I have not been able to find the Cardiaster. More- 

 over, the overlying 38 feet of chalk appears to me to have more in 

 common with this nodiilar rock than with the softer chalk above, in 

 which Mr. Price puts it. Echinoconus suhrotundiis, though not very 

 common, appears in the top of the " Grit Bed " and marks the upper 

 portion of this zone, as in Cambridgeshire, Hertfordshire, &c. The 

 limit of the nodular chalk may be taken as about the limit of this 

 zone, which I estimate to be 70 feet in thickness. This, while 

 including 38 feet of the zone of Terehratulina gracilis of Mr. Price, 

 agrees closely with the zone of Inoceramus lahiatus of Barrels. 



List of Fossils from the Zone of Rhynchonella Cuvieri. 





DoTer. 



Cambridge- 

 shire. 



Brachiolites ? 



* 

 * 

 * 



* 

 * 



* 



It 

 * 



* 

 * 



Axoffaster cretacea Lonsd 



Cardiaster pvgmseus, Fcrbes 



Cidaris perornata (spines), Forbes 



(spines) 



Cyphosoma maffnificum Ag, . 



Discoidea minima, Aq,,.. 



subucula, Leske'i 



Dixoni, Forbes 



Echinoconus globukis, Desor 



subrotundus, Mant. 



Salenia granulosa, Forbes 



Serpula plexus ? Sby 



— — antiq ua, Sby 



Terebratula semiglobosa, Sby 



Terehratulina gracilis 



striata, Wahl 



Rhynchonella Cuvieri, d/Orb 



limbata, rf'Ori 







