128 GEOLOGY OF THE ISLE OF WIGHT. 



particularly at Bognor ; the rocks on the shore at 

 that watering-place consisting of coarse sandstone 

 full of similar fossils. The lowermost or earliest 

 bed of this series, is a layer of brownish clay with 

 green sand (in some parts passing into concre- 

 tionary sandstone) almost made up of the tubular 

 shells of one species of pteropodous mollusk, the 

 Ditrupa plana, formerly called Dentalium planum, 

 (PL III. fig. 3); the Bognor rocks are full of 

 these shells. The clays and sands that succeed 

 swarm with certain marine bivalves (ostrecc, 

 myw, turritellw, pectuncull), which also occur at 

 Bognor. The Panopma intermedia (PI. III. fig. 5), 

 is a very characteristic fossil.* 



A considerable thickness of variously coloured 

 sands and clays, in which no organic remains have 

 been found, is next in order ; and then the 

 suite of deposits of the London clay teeming 

 with marine exuviae. Among the shells are 

 the species figured in PL III. figs. 1, 2, 4, 

 6, 7 : the Cardita planicosta (fig. 7), is a strong 

 and thick bivalve that abounds in some of the 

 argillaceous beds, and often attains a large 



* The position of the strata containing the Ditrupa and the Pun"/,,, a is 

 shown in the diagram, lign. 8. A few weeks since, several blocks of the 

 greenish limestone, covered with Ditrupte, were lying on the beach near the 

 spot indicated. 



