206 WORK AND RECREATION. [1867-68. 



sand and gravel is always dry) ; then the lower part of the sand 

 and gravel, in which the water is held up by the London Clay, 

 and in which all the old pump springs of London occur, is all in 

 order. In this part of the series, Unios, Cyclas, Limnea, &c., 

 might occur, and it would not be surprising that Wren should 

 have described them as he did, as the occurrence of a like deposit 

 in the gravel at Clapton or Hackney was described in some of 

 the newspapers in nearly similar terms, only about six years 

 since. Certainly the depth would not be about the level of low- 

 water mark, as the ground at St Paul's is 40 feet above the 

 Thames, and the depth to the London Clay cannot be more than 

 20 to 25 feet, but it might have been considered that " about " 

 would give the measure near enough. 



By " hard beach " I think compact subangular gravel must be 

 meant. Beneath this, " natural hard clay " applies perfectly to 

 the London Clay. Pray excuse this rather hurried scrawl, and 

 believe me to be truly yours, J. PRESTWICH. 



There is no record of published papers for this year, 

 but this is accounted for by the fact of his having 

 thrown himself with his usual zeal into the require- 

 ments of the .Royal Water Commission. Every spare 

 hour was devoted to the delineation of maps, in order 

 to show the available sources of water-supply. He was 

 also elaborating the first of his series of Crag memoirs ; 

 and although he had explored the Eastern counties 

 times without count, he went again and again into 

 Norfolk during this year to investigate some special 

 point, or to obtain some fresh piece of evidence. 



The Saturdays at Shoreham had become an institu- 

 tion, and the garden an unending interest each shrub, 

 each tree, being planted under his own immediate super- 

 intendence. These weekly visits to the garden and 

 frequent geological excursions were more than ever 

 needed for the restoration of his health, which had 

 become impaired by continued high pressure. His 



