294 The Rev. W. Buckland on the Plastic Clay Formation. 



London road about two miles east of Beaconsfteld. These with 

 other extensive beds of the same era which occur between Bulstrode 

 and Windsor, are in almost immediate contact above the chalk, and 

 appear to belong to the formation of plastic clay. The Windsor fire 

 bricks and soft sandy bricks for arches, are probably also made from 

 beds of this same formation. Mr. Warburton has been told that at 

 CI ewer near Windsor, the Thames cuts through a bed of shells which 

 he suspects to be the same as are found at Woolwich. 



We will now leave the beds of the plastic clay formation in the 

 London basin, to trace them in the same relative position on the 

 coast of Sussex. 



A similar deposition of sand to that of Reading containing a breccia 

 of chalk flints as its lowest stratum, (about three feet thick) was 

 noticed by the Honourable H. G. Bennet and myself in July, 1814, 

 between Newhaven and Beachy Head, in the cliff at Chimting 

 Castle half a mile on the east side of Seaford. The sand here is 

 fawn coloured passing into olive with flakes of mica almost a line in 

 diameter, and occasionally contains irregular veins and masses of 

 tubular concretions of iron-stone. Its greatest thickness is under 

 50 feet. Mr. Warburton informs me that he has seen similar con- 

 cretions in the same stratum of sand at Sudbury in Suffolk, in im- 

 mediate contact above the chalk. Under this sand at Chimting the 

 breccia of the lowest bed forms an ochreous pudding stone composed 

 of sand and chalk flints, (the latter both rolled and angular) the 

 whole being strongly united by a ferruginous cement, and the flints 

 covered externally with a green coating like those in the oyster bed 

 at Reading. Specimens of this breccia have been presented to the 

 Society by the Hon. H. G. Bennet. At Chimting Castle there is 

 but a small insulated portion of these strata immediately incumbent 



