170 GEOLOGY OP THE ISLE OF WIGHT. 



Bembridge Marls. 



Above the Bembridge Limestone lies a series of freshwater, 

 estuarine, and marine clays and marls. These attain a thickness 

 of about 120 feet at the east end of the island, but thin away to 

 about 70 feet towards the west. The Bembridge Marls were 

 divided by Forbes into the Oyster Bed, Lower Marls, and Upper 

 Marls. But there is no break or definite boundary between the 

 Upper and Lower Marls, and no marked palseontological change 

 anywhere in the series, except that the marine shells are confined 

 to the base. The Marls are therefore here treated as one 

 subdivision, in which certain marked beds can be traced for 

 considerable distances, but which it is not necessary or practicable 

 to separate into smaller sub-groups, except locally. 



At the east end of the Island, where the beds are thickest, the 

 following section was measured by Forbes : — 



Bembridge Marls in Whitecliff Bay. 



Variegated yellow and brown clay (occasionally sandy) con- 

 taining lines of nodular concretions, but no fossils 



Pale shaly clays, the lower part with a band of septarian con- 

 cretions, containing Paludina lenta and other shells 



Lead-coloured clays, laminated above, paler below. Paludina 

 lenta, Melanopsis, Melania turritissima, occasional Cyrena, 

 and I'emains of Fish ----- 



Pale bluish sands and sandy clay. Melania turritissima, 

 Melanopsis fusiformis, Paludina lenta, Fish, Seeds 



Sandy grey limestone occasionally passing into marl ; some- 

 times very fossiliferous, often concretionary with few fossils. 

 Bulimus elUpticus, Achatina costellata, Limncea longiscata, 

 Melania costata, Paludina lenta, Cyrena transversa, Unio, 

 Chara Wriffhtii - - 



Red marl, without fossils - - . . - 



Pale blue laminated sandy clay, containing a few pebbles of 

 limestone and flint. Traces of Fish - - . 



Variegated red and green marls. Cyrena ; fragments of 

 Trionyx incrassatus ------ 



Clays with whitish streaks. Melanopsis fusiformis, Paludina 

 lenta .----.. 



Seam of Serpula. 



Clay, with Cyrena semistriata, C. pulchra, C. olovata, C. 



obtusa, Cerithium mutabile and Melania costata - -40 



Hard imfossiliferous blnish septarian stone [probably the 



equivalent of the Insect Limestone further west] - _ 6 



Dark shaly clay. Cyrena semistriata - - - -26 



Green sandy beds. Ostrea vectensis, Cytherea incrassata, 



Mytilus affinis, Nucula similis, &c. - - - .-20 



Whitish sands interstratified with fine stripes of clay ; occa- 

 sional pebbles. Lines of Cyrena semistriata and occasional 

 Cerithium - - - - - - -20 



Grecnisii marls, with lines of white nodules in the lower part 3 



Bembkiuge Limestone. 



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