The Rev. W. Buckland on the Plastic Clay Formation. 281 



green sand, (No. 2.) The same barrenness of organic remains is 

 noticed in the purest beds of the French plastic clay, and by Mr. 

 "Webster (Geol. Trans, vol. 2, p. 200), in the plastic clay of the 

 Isle of Wight and Corfe Castle. 



The section given by Dr. Brewer, in the Phil. Trans, for 1700, 

 differs as little as might be expected from that which is now ex- 

 posed at Reading. Beginning from the bottom, he gives the fol- 

 lowing strata : 



No. Feet. 



1. Chalk rock — 



2. Green sand containing oyster shells - - - 2 



3. A bluish sort of clay, very hard, brittle, and rugged 



(called pinney clay) ; it is of no use - .- -3 



4. Fullers' earth ------- 2f 



5. Clear fine white sand - - - - - 7 



6. Stiff red clay used for tiles, the depth of which, he says, 



could not conveniently be taken from the heighth of 

 the hill, at the top of which, he adds (immediately 

 under 2 feet of common earth) the red clay appears, 

 and is used for tiles. 

 The thickness of the beds which Dr. Brewer did not measure 

 was probably made up of those from No. 7 to No. 12 inclusive, 

 in the section I have given, in which also the beds below No. 6 

 correspond very nearly with his account, which I had not seen till 

 my own was finished as it now stands. 



In a hill called David's Hill, west of the town of Reading, on the 

 opposite side of the Kennet to that of the Catsgrove brick kilns, 

 and about one quarter of a mile distant from them, are other large 

 quarries of brick earth, in which many of the subdivisions which 

 have been noted at Catsgrove are not to be recognised, and the 



