230 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 25, 



In the greensands and brown clays of stratum " B " at Alum 

 Bay organic remains abound, dispersed in distinct masses and groups. 

 The lower part of the stratum, where it is much mixed with green- 

 sand, contains very few shells with some vegetable remains. At 

 about twenty-seven feet from the bottom the clay becomes almost 

 free from greensand, and contains numerous patches of the small 

 Nummulites elegans. Above these the Corbula pisum abounds. 

 The clay then again passes into a clayey greensand, a change ac- 

 companied by tlie almost entire disappearance of organic remains. 

 A layer of Septaria and small flint pebbles then form an abrupt line 

 of separation to a dark grey clay full of fossils, of which the principal 

 are Pleurotoma colon, Voluta luctator^ Fusus longcevus, Conus dor- 

 mitor and Nummulites IcBvigatus. The fossils again become scarcer 

 in ascending, occurring only in irregular patches, and almost disap- 

 pearing before the top of the stratum is reached. 



The other fossils of this stratum " B " are well-known as common 

 London clay species, and need not here be enumerated. In addition 

 to the usual species I may however mention, that I found one speci- 

 men of the Cyrena obovata, and a Spatangus resembling the large 

 one of the calcaire grossier (see description of Plate). 



At White Cliff Bay, where the non-fossiliferous strata are limited 

 to the sands No. 5, about 100 feet thick, we find a great vertical 

 development of animal life, corresponding however only in part with 

 that of stratum " B " at Alum Bay. At Alum Bay its vertical 

 range is about 250 feet, and the species are not much grouped ; 

 whereas at White Cliff Bay its vertical range is about 600 feet, and 

 the species are for the most part distinctly grouped, forming frequent 

 bands of the Venericardia planicostata, Turritella imbricataria and 

 Ostrea, The Venericardia and Turritella abound in the centre of 

 this group, in one part of w hich also Foraminifera are common, and 

 in one part of it I have found a few Miliolites resembling the M. 

 saxorum of Lamarck ( Trinocularia, D'Orb.) and some Gyrogonites. 

 The following are among the species I obtained from these strata : — 



Venericardia planicostata. Solen obliquus. 



globosa. Fusus longaevus. 



Turritella sulcifera. Calyptra^a trochiformis. 



Nummulites elegans. Corbula pisum. 



lse\igata. Turbinolia sulcata. 



Nucula similis. Pyrula, 1 sp. 



Sanguinolaria Hollowaysii. And a Natica and Cerithium of the 

 Pecten corneus. same species as occur in the over- 



Ostrea flabeUula. lying freshwater deposits. 



Mr. Bowerbank was the first to notice the fossils of these beds, 

 which he, I think, justly considers to be the equivalent of the Brack- 

 lesham Bay strata, from which he and Mr. Edwards have procured 

 a much larger and a very beautiful series of fossils. The upper 

 beds of this divission corresponding with stratum " B " of Alum Bay 

 are most indistinctly exposed at White Bay, and have yielded fewer 

 fossils : consequently the fauna above-mentioned, occurring low 

 down in this division, must not be considered the equivalent in time 

 of that at Alum Bay, where, as at Barton, the large development of 



