The Rev. W. Buckland on the Plastic Clay Formation, 293 



It is mentioned by Woodward that the Woolwich shells are found 

 at Camberwell and Beckenham, on the north-west and south-east 

 sides of the Sydenham Hills. I have other authority for their occur- 

 rence at the following places on the south side of the Thames, 

 Camberwell, Redriffe Tunnel, New Cross, Lewisham, Blackheath, 

 Woolwich, Plumsted, Beckenham, Bromley, Chislehurst, Bexley, 

 Cockleshell Bank, two miles south of South Fleet, Windmill Hill near 

 Gravesend, and Higham on the Thames and Medway canal. They are 

 found also at Rungewell Hill near Epsom, and at Headley between 

 Epsom and Dorking. 



These localities seem sufficient to warrant us in concluding that 

 the formation of plastic clay extends over a large space in the south 

 portion of the valley of the Thames from Reading to Gravesend.* 



Woodward mentions oysters as being found on the north side of 

 the Thames in a stratum of sand that covers the chalk near Hertford ; 

 this probably is one of the oyster beds of the plastic clay formation. 



I remember that in 1806, fire bricks were burnt from some beds 

 of fine sand and clay in the Park at Bulstrode, by the late Duke of 

 Portland, and that moulds for refining sugar were (and are still) 

 made within a mile of it, at some clay pits on the north side of the 



* In Chislehurst, at the north-west angfe of the park at Camdeu Place, the section of a 

 chalk pit displays a great thickness of the ash coloured Woolwich sand, separated from 

 the chalk by the thin pebble bed as at Reading. 



The thick Woolwich sand (No. 3,) occurs also at Bexley, where (as is the case in 

 many of the woods about Dartford) shafts 40 or 50 feet in depth have been sunk through 

 it at an early period for the purpose of extracting the subjacent chalk, as is now done at 

 Reading, and Plumsted brick kiln. Mr. Hasted, in his History of Kent, conjectures that 

 many of these quarries were excavated by the Saxons, as places of retreat in times of 

 danger. He states that some of them are 20 fathoms in depth, and that they are to be 

 found also near Petersham, and at Fritwood on the south of IWurston Passage near 

 Milto<s. The explanation that is suggested by the geological position of all these places 

 appears to be much more satisfactory. 



Vol. iv. 2 p 



