166 MOEL TRYFAEN. [1861. 



thence by St Lou to Cherbourg, and on by rail to 

 Paris, where several days were spent in viewing the 

 collections in the Nicole des Mines and in the Jardin 

 des Plantes. 



This French excursion was one of close work. The 

 heights at which gravel and other "Drift" were found 

 are recorded, and the composition of these in each 

 locality is carefully noted. He was preparing for an 

 important paper on the geological age of the Drift de- 

 posits, which was read next year at the Royal Society. 



The letter which follows was probably written at 

 this date : 



J. Prestwich to H. Falconer. KENT TERRACE, Saturday [1861]. 



MY DEAR FALCONER, City business drove yesterday morn- 

 ing's work out of my head for the rest of the day. 



On my return at night I looked over my Grays specimens, 

 and now send you the results of Heer's examination. I hope 

 next winter to clear up some of the points of doubt, and add to 

 the list before publication. Of the Mundesley woods, cones, &c., 

 the only specimens that could be determined were, as I told you, 

 Pinus abies common ; Pinus sylvestris rarer together with a 

 seed vessel. . . . 



PLANTS GRAYS. 



Quercus robur, var. sessiliflora ? Hedera Helix. Vaccinium 

 myrtillus ? ? ? Pteris aquilina ? ? Alnus ? Cyperus ? Fagus ? ? 

 Eubus. Populus. Equisetum and Phragmites. 



This is very good so far. 



In September he was at work at Highbury with his 

 friend Mr Alfred Tylor. 



J. Prestwich to Sir Charles Lyall. Sept. 16, 1861. 



MY DEAR SIR CHARLES, You will find the best account of 

 Trimmer's Moel Tryfaen case in his paper " On the Drift of the 

 Cambrian Chain." He mentions only two species of shells, the 



