208 O. Dowher — Water-sujjply of East Kent. 



Mr. W. Whitaker, B.A.Lond., Assoc. Inst. C.E., F.G.S., of H.M. 

 Geological Survey, has kindly placed at my disposal some well- 

 sections not before published, chiefly that of the Heme Bay Water- 

 woi'ks at Ford and the Whitstable Waterworks, which are in the 

 Tertiary area north of Canterbury. But it is not certain from these 

 data whether the water is derived from the Thanet Beds or the 

 Chalk. In the case of Whitstable, at a height of 4H feet above 

 Ordnance Datum, the well, 400 feet deep, pierced the London Clay 

 at 69 feet, the Tertiaries at 240 ft, and penetrated the Chalk 160 feet. 

 The water-level is stated to be 35 feet down, and the yield 220 

 thousand gallons daily. And in the case of Ford, reaching a total 

 depth of 260 feet, piercing the Lower Tertiaries at 110 feet, and 

 penetrating the Chalk 50 feet — the watei'-level standing 26 feet 

 down. From which facts it seems that the Chalk in both cases was 

 the source of the supply. 



The well-sections in the Isle of Thanet, which have (with the 

 exception of one at Mr. Cobb's Brewerj', Margate) been^ sunk but 

 little below the sea-level, have only yielded water at about that 

 level. In the case of Mr. Cobb's well, which reached a depth of 

 317 feet, no spring was met with. Artesian wells at Minster at 

 a low level, piercing the Thanet Bed to some 20 feet or so into the 

 Chalk, yielded water springs flowing to the surface. 



The permeability of the Chalk in Kent was shown some years 

 ago by an old member of our Society, Mr. Bland, of Sittingbourne, 

 in some tables which he published showing how one well was 

 influenced by another, and how they all fluctuated with the rainfall 

 of the seasons. Mr. Prestwich has in his memoirs ^ made use of it, 

 and I am indebted to the Eev. C. J. Wimberley, of Sibertswold. 

 Yicarage, for a copy of this interesting paper. His conclusions with 

 respect to the permeability of the Chalk have been corroborated in 

 all the observations I have made, and the truth cannot be too often 

 repeated to those who are engaged or interested in sanitary matters. 

 It must be of the first importance to consider this in relation to the 

 sewage and health of towns. Sewage matter will contaminate a 

 large area of Chalk, if precautions are not taken. 



The section I have made would show how regularly the lower 

 beds dip towards Canterbury ; but if I had continued the section to 

 Whitstable nearly in the same line, it would be apparent that the 

 Gault must rise, or there would be an enormous thickness of Chalk 

 to be accounted for had the Gault continued at the same dip. It is 

 assumed that the bore at the Chartham Asylum touched the Gault. 

 Mr. Whitaker places the bottom of the bore at that horizon. From 

 the specimens I have seen at the Canterbury Waterworks, I doubt if 

 they quite reached the Gault. There seems also to be a slight 

 synclinal of the Thanet beds in the valley of the Stour east of 

 Canterbury — the Isle of Thanet being on an anticlinal. 



It would seem as if the Lower Greensand in this neighbourhood 

 cannot be reckoned upon as a source of water-supply, firstly, because 



1 " The "Water-bearing Strata of the Country round London," and "Manual of 

 Geology." 



