Mr. Webster on the Strata lying over the Chalk. 199 



Richmond Park is on this stratum, and Woodv/ard frequently 

 refers to this place in his Histoiy of Fossils ; but there are no longer 

 any sections to be seen there, the spot being covered by buildings. 



Wells of 70 feet deep have been dug at Harrow-on-the-hill ; and 

 several in London between 200 and 300 feet deep. At other places on 

 rising grounds the depth of this stratum is much greater. In digging 

 a well for Lord Spencer, at Wimbledon, they were obliged to go 

 530 feet deep before they got through it to the sand which con- 

 tained water. At Primrose-hill, near Hampstead, a well was dug 

 some years ago to the depth of 500 feet without success. 



This considerable formation may not only be traced on the north 

 side of Kent and Surrey, but almost the whole counties of Middle- 

 sex and Essex are composed of it. At South-end, and Leigh in 

 Essex, there are good sections of it. But not having an opportunity 

 of visiting the coast farther to the north, I am unable to speak with 

 certainty respecting the various strata to be observed there. 



The cliffs at Walton and Harwich, in Essex, have been best de- 

 scribed. From various accounts the lowest part consists of blue clay, 

 the fossils of which agree generally with those of Hordwell, Sheppey, 

 &c. This clay is covered by deep beds of gravel, sand and marl, 

 containing not only great quantities of fossil shells but also the 

 remains of land animals. 



• From the confused manner in which these shells and pebbles lie^ 

 as described by Mr. Dale in his history of Harwich, there can be 

 no doubt but that the strata containing them are frequently alluvial j 

 though in the cases where he describes them as lying in patches of 

 particular genera, we may suppose that portions of the original strata 

 remain undisturbed. 



Many of these latter fossil shells must belong to some of our latest 

 strata : they are described as scarcely mineralized, very friable, and 

 of a dead white colour. 



