94 TERTIARY MEMOIRS. [l854. 



part, and others have taken it up with great effect. I should 

 rejoice to see you in Cambridge any time that I am resident. 

 For the next two months I shall be a prisoner in the Cathedral 

 Close. Very truly yours, A. SEDGWICK. 



J. Prestwich to Sir Charles Lyell. NORWICH, 3rd July 1854. 



MY DEAK SIR CHARLES, I shall be in town in a day or two, 

 but write now to answer your question about the sand-pipes on 

 the escarpment of the N. Downs. 



I drew attention to the fact in my paper read in March, on 

 account of its importance in showing at how very recent a date 

 the last most important denudation of the Weald took place. 

 The section I gave agrees with your sketch. The slope, when- 

 ever I have seen it, is quite bare, and shows no signs of an old 

 cliff. There is, it is true, a little chalk rubble, but that might 

 arise from pluvial action. I remain, my dear Sir Charles, yours 

 very truly, J. PRESTWICH. 



In 1854 we have also an array of papers which 

 appeared during that year. The one which stands 

 first on the list is the second of his Tertiary memoirs, 

 " On the Structure of the Strata between the London 

 Clay and the Chalk in the London and Hampshire 

 Tertiary Systems. Part II., The Woolwich and Head- 

 ing Series." In this paper an account is given of 

 the impressions of fossil leaves from a bed of clay in 

 the railway - cutting for the Newbury branch line, 

 through the hill immediately west of Heading. An 

 excellent plate shows these beautifully preserved im- 

 pressions of plants, and in a note by Sir Joseph D. 

 Hooker, also accompanying Prestwich's paper, the 

 botanist remarks that, " both in a geological and 

 botanical point of view, the Reading fossils are of 

 first-rate interest and importance, as presenting us 

 with an association of forms so entirely analogous to 

 those now existing, as to leave no grounds for assum- 



