Dr. Wright on the Geology of the Isle of Wight. 19 



At Headon Hill this bed is very fossiliferous, and contains 

 there Cyrena ohovata in great profusion in a black clayey matrix 

 with lignite and much vegetable debris. 



From the sandy seams at Bramble Chine I collected many 

 hazel-nuts in a good state of preservation. 



No. 6. Underlying the Potamomya bed is a band of firm 

 bluish green sand, tolerably compact. This appears to form the 

 transition bed to the estuary series below it. It rises on the 

 shore 1620 feet north of Bramble Chine, forms a prominent belt 

 in the cliff, and in some places a ledge, by the foundering of the 

 superincumbent clays and sands : measures about 3 feet, and 

 is overlaid by laminated clay rich in Potamomya. 



No. 7. Blue clay with few fossils, 3 feet. 



No. 8. Bands of nodular ironstone resting on blue sandy clays ; 

 rises 55 paces south of No. 6, and runs out at Warden Point. 

 Beautiful slabs of this bed from 4 to 5 inches thick lie along the 

 shore, and in most of the cottages household specimens may be 

 seen. The clays and nodules contain Cyrena obovata, C. cycla- 

 diformis, Poiamides margaritaceus, P. ductus, Cytherea incras- 

 sata ; Melanopsis, Nematura, as in the Neritina bed. This fer- 

 ruginous bed measures about 20 inches. 



No. 9. Gi*ay mottled sands, without shells, 18 inches. 



No. 10. Dark stiflF tenacious clay. This is a very rich bed, 

 and many of the shells which are of estuary origin are beautifully 

 preserved. 



It rises on the shore about 100 paces to the north of Lynchen 

 Chine, is nearly horizontal for a considerable distance, and is 

 much covered by debris, bait is seen in situ beyond Bramble Chine. 

 It is lost at Colwell and reappears in the cliff at Warden Point, 

 passing out a short distance beyond. 



I collected from this bed Cyrena obovata, C. cycladiformis; My- 

 tilus affinis, in great abundance ; Ostrea, two species ; Cytherea in- 

 crassata, Potamides margaritaceus, Melania muricata, M. fasciata, 

 M. costata, Melanopsis fusiformis, Fusus labiatus, Nerita aperta, 

 very few of Neritina concava, and Natica depressa. It measures 

 about 3 feet. 



No. 11. A dark-coloured stiff clay, without shells; measures 

 18 inches, with a shelly band of blue clay 6 inches in thickness, 

 containing the same genera and species as No. 10, with nodules 

 of ironstone in some parts of its course. These two beds indi- 

 cate an estuary condition during the period of their deposition. 



No. 12. " The Ostrea bed " rises on the shore at the south 

 side of Lynchen Chine, is much foundered at its origin, but is 

 well seen in situ in the walls of Bramble Chine, in the escarp- 

 ment south of that gorge, in the cliff at Warden Point, and at 

 Alum Bay, high up on Headon Hill.. 



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