21 



pockets or pijjcs in the chalk, tuul that the cause of the subsidence 

 is the drawing away of the subsoil by the action of water. They 

 certainly have no resemblance to the artificial holes found so fi-e- 

 quently in adjacent parts of the county. The water-level under 

 Blackhcath is about Ordnance datum, and it is just possible the 

 di'ainage works carried on by the Metropolitan Board have dis- 

 turbed the stability of the pebble beds and sand by removing the 

 water. It appears, however, to me far more probable that the 

 pumping up of the water by the Kent Water Works, at Deptford, is 

 one, if not the principal cause, of the subterranean drainage, and 

 consequently of the subsidence, by drawing away sand and chalk in 

 mechanical suspension. I am told that about 9,000,000 gallons of 

 water per day are lifted at the pumping station of the Kent Water 

 Works at Deptford, which is near the base of the table land. 

 We know that the unfiltered water sent by this Company for our 

 consumption, ft-ee as it is fi-om organic life, is fully charged with 

 chalk and earthy matter. Our cisterns show a deposit of fine sand 

 and chalk, which is fi'equently astounding. 



The Council considered the proposal to raise special funds for 

 the purpose of conducting explorations on the site of these sub- 

 sidences; but regarding the question as one of archaeological 

 rather than scientific interest, they did not think it desirable to 

 ask you, as a Society, to join in taking up the work. 



Gentlemen, I thank you for the courteous attention with 

 which you have listened to these observations; and I feel it is 

 incumbent upon me, before closing this address, most distinctly 

 to recognize the zeal and ability of our two Honorary Secretaries, 

 to whose exertions in so many ways the Society is indebted. I 

 would very cordially express my personal obligations to them, and 

 at the same time I would heartily thank those members who, by 

 the papers and observations they have contributed, as well as by 

 their attendance at the meetings, have assisted in promoting the 

 successful working of the past year. May the cuiTent year be 

 even more successful than the last. 



