PRESTWICH — WOOLWICH AND READING SERIES. 83 



several subordinate beds of sand. At Bishopstoke, near Winchester, 

 on the contrary, the mottled clays have nearly disappeared, ^and ap- 

 pear to be replaced, in part or wholly, as at Addington near Croydon, 

 by sands and thick beds of rounded flint-pebbles in yellovr sand. In 

 one pit at Stoke Common they are 1 2 to 15 feet thick, and exactly 

 resemble the shingle beds to the S.S.E. and E.S.E. of London. 



Taking an easterly course from this line, the mottled clays and 

 some associated pebble beds * range past Chichester, Arundel, to 

 Highdown hill near "Worthing, to the north of which, at the village 

 of Clapham, a thick stratum of small rounded flint-pebbles overlies 

 the clays as at Croydon ; but whether these pebbles belong to the 

 Basement-bed of the London clay or to the mottled clay group, there 

 is at present no evidence to show. Wick House hill on the west of 

 Brighton is capped by a few beds of mottled and carbonaceous clay 

 reposing on sand over chalk — the section is incomplete, and no fossils 

 have been fomid. Passing thence to the detached outlier at New- 

 haven, we find a totally different group of strata ; a thick bed of 

 sand overlying the chalk, succeeded by a series of laminated grey 

 clays containing numerous fluviatile and estuarine shells. 



Particulars of this section have been given both by Dr. Mantellf 

 and Dr. Buckland J. Owing to the frequent fall of the cliffs, the 

 section, however, is constantly varying. I have never been able to 

 see it in perfectly clear sequence ; but still, as there are some points 

 which I have noticed in addition to those described by former ob- 

 servers, I herewith give a rough account of the section, premising 

 at the same time that, owing to the impossibility of approaching 

 some parts of the cliff, it must be considered only as approximative. 



Section, upper part of Cliff, Castle Hill, Newhaven. 



Feet. 

 Gravel of subangular flints and tertiary flint-pebbles in ochreous and 



ferruginous sandy clay, averages about 6 



i. Grey clay passing into dark yellow sand and then again into grey clay : 

 no fossils. [Were it not that part of the upper portion of this bed 

 presents a mottled red appearance, I should have been disposed to 

 consider it as the lower part of the London Clay ; even now I am not 

 satisfied but that the small quantity of mottled clay observed may 

 not belong to the overlying drift, the line of separation being at that 



spot perfectly indistinct and very irregular.] 12 



h. Round flint-pebbles in grey clay and yellow sand (Bt.-bed L. C. ?) ... I 



g. Laminated grey clay with seams of yellow and ferruginous sand 8 



f. Mass of concreted oyster rock ( Ostrea Bellovacina) 2 



e. Layers of comminuted shells, yellow sands, grey clays with well-pre- 

 served shells, and with an intermediate bed of grey clayey sand 6 



d. Yellow, light brovra, and red sand in layers, with seams of laminated 



grey clay — traces of vegetable matter 5 



Carryforward 40 



* It is uncertain whether these beds are continuous or not between Botley and 

 Clapham. 



t "On the Geological Structure of Sussex," and Trans. Geol. Soc. 2nd Ser. 

 vol. iii. p. 204, 



J Trans. Geol, Soc. vol. iv. p. 296. 



G 2 



