192 Mr. Webster on the Strata lying over the Chalk 



Turning round this promontory, the lower chalk and chalk 

 marl are seen at the bottom of the cliff and rising to the north-east, 

 where they soon take place of the chalk, forming a mouldering 

 slope at South Sea houses ; they there give place to the green sand, 

 which continues some way, then dips, and is covered by a flat 

 beach extending many miles along Pevensey bay. It is almost 

 needless to observe that the cliffs from Rottendean to Beachy head 

 are oblique vertical sections of the South Downs, and have been 

 formed by the action of the sea. 



On entering the London basin at the south side from the sea, 

 after passing the chalk cliffs at North Foreland and Margate, the 

 blue clay makes its first appearance at Reculver ; and at Swale cliff 

 and Whitstable it is again seen. 



But the Isle of Sheppey, consisting entirely of this stratum, and 

 whose lofty cliffs on the north side furnish very extensive sections, 

 affords the best opportunity for studying it. 



Of this island, the northern half consists of a range of hills, of 

 above 200 feet in height. These are cut down vertically by the 

 action of the sea, which occasions the cliffs continually to fall : 

 whole acres of land sometimes coming down at once ; in conse- 

 quence of which, the island must in a course even of a few centuries 



presence of mind to escape over the rent tliat was forming at some distancrjfrom the edge 

 of the cliff. In a few seconds, the mass of chalk which he had stood on, to the extent 

 of 300 feet in Icngtli, and 70 or 80 in breadth, fell with a tremendous crash. In going 

 from Ncwhaveii ro\md Beachy Head, under the clilf at low water, I passed over these 

 ruins, which were truly terrific, and observed that their fall had been occasioned by the 

 sea acting on the chalk marl, and thus undermining the chalk ; the former from the dip 

 of the strata, just begins to appear at the bottom of the clilf at this spot. It may be 

 |)roj)cr to mention that this place is highly deserving to be visited, on account of the 

 fossils to be seen in the chalk and green sand ; among these I remarked many large 

 madrepores, and some very large and entire shells of the fibrous kind, the fragments of 

 which are so numerous in the chalk. 



