a;^^ 



255 



Dr. FiTTON on the Strata below the Chalk. J 87 



from east to west : giving, 1st, A section from beneath Bembridge Down 

 to the middle of Sandown Bay ; Sndly, The opposite side of the curve, 

 from Bonchurch Cove, eastward, towards the same point; 3rdly, The succes- 

 sion of beds beyond Rocken-End, north-westward, to the geological centre, 

 or lowest point, on the south-west range of the coast; and 4thly, The 

 series from the chalk under Afton Down to Brook Point. This will involve 

 some apparent repetition, as the strata in all the sections are essentially the 

 same ; but it will perhaps be the best mode of assisting the inquiries of 

 those who wish to become acquainted with this district. 



(97.) Sectional List of the Strata from the south-west of Bem bridge Dottn 

 to the middle of San down Bay. 



The Section begins at the bottom of the flinty chalk. Beds very thick and massy. "§ .1 



The flints small and disseminated. I-'S 



Paces. o ■<; 



— 510. Lower White Chalk, without Flints. 



— 255. Tiiis part of the beach is occupied by ruined masses from above. The base of the 

 cliff, where accessible, seems to consist of knobs of white chalk, bedded in a greyer mass. 

 The stratum is defined by a layer of distant, insulated flints, which separates it from the 

 flinty chalk above. Dip about 65°. Strike, about 6° north of west ; which is very 

 nearly the direction of the coast 



255 — 510. The finest and tliickest beds of pure white chalk. Dull; not very white chalk ; - 

 easily scratched by the nail. Beds, 3 or 4 feet thick ; separated by layers, 5 or 6 inches 

 thick, of chalk like the rest, but interlaced with a kind of r>etwork of very grey matter. 

 Dip, 60° north. Strike, 74° west, almost coincident with the trend of the shore 



350. Inocerami, much crushed. At 450 paces, the same, but less frequent. At 500, 

 dip, 60° north ; strike, 69° west of north 



510 — 7^3. Marly and Grey Chalk. 



511. Outcrop of a seam of greyer chalk 



526. In the grey chalk a layer of yellow harder knobs 



540. A bed of very uniform grey chalk, 6 to 8 feet in thickness exposed 



600. A thick bed of grey chalk, as at 540 ; and the same rubbly yellowish layer as at 526 . . 



650. Grey chalk ; thick uniform beds, 3 or 4 feet 



700. Grey and white chalk, in alternating layers. This alternation extends about 20 feet 

 up the cliff,' which shelves back 



750. At a breaking away of the talus, the outcrop of the grey chalk is superbly seen. 

 Alternating, dark grey, almost blue, layers, and white, like a striped riband. Corals oc- 

 cupy the lower 5 feet. [The same appearances are very remarkable at the foot of Blanc 

 Nez, on the French coast near Calais.] 



obliquity of the section to their planes, I have stated the horizontal spaces occupied by the strata 

 at the base of the cliff, which give at least a comparative view of their proportions. I find, from 

 the mean of several comparisons, that my own paces (which are somewhat shorter than Sir J« 

 Herschel's), are about 43 (strictly 42'77) = 100 feet: and in my section the Upper green-sand 

 occupies 196 paces on the shore; the Gault 94 ; Lower green-sand 840 ; the Wealden, to the cul- 

 minating point of the Hastings sand, about 2000 ; — of which space the Weald-clay may be 600, 

 and the Hastings sand about 1400, from their first rise to the middle or top of the saddle. 



255 



273 



