66 WOLLASTON MEDAL. [l849. 



he covers more than seven closely written pages of 

 foolscap describing the functions of trees and foliage 

 in purifying the atmosphere. He dwells on the won- 

 derful part which leaves perform in decomposing the 

 excess of carbonic acid gas and setting free its oxygen. 

 The minute care and detail shown in this letter char- 

 acterised all that he ever undertook. 



In 1849, while Sir Henry De la Beche was President, 

 Joseph Prestwich was awarded the Wollaston Medal 

 of the Geological Society for his researches in the 

 coal district of Coalbrook Dale, and for those subse- 

 quently carried on in the Tertiary Districts of Lon- 

 don and Hampshire. The President emphasised this 

 honour by remarking that he was aware that for these 

 geological researches the time which the recipient of 

 the medal had at his disposal could " only be snatched 

 at intervals from the cares of commercial life." We 

 cannot do better than quote the reply : it summarises 

 in happy terms the benefits derived from a study of 

 his science. After expressing his grateful acknow- 

 ledgments, the medallist proceeded to say- 

 It is true that I entered upon this field as a student and for 

 relaxation, but the interest and difficulties of the subject speedily 

 induced me to take it up with more earnestness and determina- 

 tion, and eventually led me to extend the inquiry over an area 

 which I, at first, never contemplated. 



The Tertiary geology of the neighbourhood of London may be 

 wanting in beauty of stratigraphical exhibition and in perfect 

 preservation of organic types, but in many of the higher ques- 

 tions of pure geology, in clear evidence of remarkable physical 

 changes, in curious and diversified palseontological data, however 

 defaced the inscriptions, which is after all but a secondary point, 

 few departments of geology offer, I think, greater attractions. 



The pleasure I have derived from the study of the remarkable 

 phenomena which have come before rae in the course of the in- 



