450 



In the year 1834, Mr. John Randell of Mortlake, being desirous 

 of procuring a large supply of spring water, sunk a well on his pre- 

 mises, and within 100 feet of the Thames. 



In the first instance, an augur seven inches in diameter was used 

 in penetrating twenty feet of si^perficial gravel mixed with marl, and 

 200 feet of London clay. An iron tube, eight inches in diameter, was 

 then driven into the opening to dam out the land springs and the 

 percolation from the river. A four-inch augur was next introduced 

 through the iron tube, and the boring was continued, until the Lon- 

 donclay, having been perforated to the depth of 240 feet, the sands of 

 the plastic clay were reached, and water of the softest and purest 

 nature was obtained ; but the supply was not sufficient, and it did not 

 reach the surface. The work was proceeded with accordingly, and after 

 55 feet of alternating beds of sand and clay had been penetrated, the 

 chalk was touched upon. A second tube, 4| inches in diameter, was 

 then driven into the chalk to stop out the water of the plastic sands, 

 and through this tube an augur 3^ inches in diameter was intro- 

 duced and worked 35 feet into hard chalk abounding with flints. 

 To this succeeded a bed of soft chalk into which the instrument 

 suddenly penetrated to the depth of 1 5 feet. On the augur being 

 withdrawn, water gradually rose to the surface and overflowed in 

 considerable quantities, the supply averaging, for a time, 5000 

 gallons daily. 



The general summary of the work is as follows : 



Feet. 



Gravel 20 



London clay 240 



Plastic sands and clays 55 



Hard chalk and flints 35 



Soft chalk 15 



305 



The expense of the work did not exceed 3001. With respect to 

 the chalk itself being the reservoir whence the water is obtained, 

 Mr. Richardson mentioned an analogous case in the cliff on which 

 stands Dover Castle, where water issues from a bed of soft chalk marl 

 between the chalk with flints and that without flints*. 



A paper "On the Strata usually termed Plaistic Clay," by John 

 Morris, Esq., and communicated by the President, was then read. 



The author commences by objecting to an arrangement of tertiary 

 formations in different countries according to the classification of the 

 Paris basin by MM. Cuvier and Brongniart. He then refers to the 

 memoirs of Mr. Webster, Dr. Buckland, and Mr. Richardson, on the 

 strata immediately above the chalk in England, and proceeds to show 

 that they ought to be considered as belonging to the London clay. 



For the sake of convenience in arranging their organic remains, 

 Mr. Morris makes three divisions of these beds : 1 . those containing 



* Conybeare and Phillips, Outlines, p. 88. 



