174 GEOLOGICAL MAP. [l863. 



to give to Eamsay as required. Whether I shall do anything 

 further with them I know not. 



When the new map was commenced, I gave Mr Best my rough 

 MS. maps, and from them he reduced all the London Basin 

 district, with the exception of the portion adjacent to and west of 

 Newbury. The Eastern counties I had not so accurately sur- 

 veyed, and therefore only laid them down from my note-book and 

 recollection. 



I send you some of my working maps that you may judge of 

 the extent of work, which, though long and laborious, was to me 

 for many years a source of great pleasure, recreation, and health. 



I have received your parcel, which I shall have much pleasure 

 in taking to M. Lartet, and I am, ever truly yours, 



J. PKESTWICH. 



P.S. I have not always kept to the same colours. I com- 

 menced the Chalk in pink after Buckland, but ended in having 

 it uncoloured, as also the marsh lands. The Gault and Upper 

 Greensand count for nothing, being [on] a more general plan to 

 match the boundary of the Chalk and Tertiary outliers. The 

 North Down Crag I have also only put in red outlines. 



In his address to the Geological Society in 1865, Mr 

 W. J. Hamilton referred to the publication of a new 

 edition of the Greenough Geological Map of England 

 and Wales, mentioning the name of Mr Prestwich 

 among " the most active contributors to this work." 

 He states that " Mr J. Prestwich has supplied the 

 geological data for the Tertiaries round London and in 

 Kent, and the Bagshot series in Surrey and part of 

 Berkshire, from his own MS. notes on the 1-inch 

 Ordnance maps, at which he had worked from 1835 to 

 1855. From the Newbury district to the Isle of Thanet 

 and Harwich the new map adopts Mr Prestwich's 

 divisions and outlines as far as could be done with the 

 imperfect topography of the original plates. Mr Prest- 

 wich also undertook to put in the Chalk, Crag, and Drift 



