170 MEMOIR ON DRIFT. [l862. 



last paper. I am glad that you took the subject in hand, for I 

 fancied that others, if not poaching on your land, were at least 

 establishing " squatter rights " on what you had left unoccupied. 

 It was with feelings akin to wonder that as the paper proceeded 

 I found that you had become a Glacialist, but for a long time I 

 fancied that you were putting such conditions in a hypothetical 

 form only, and that the coup de grdce was at last to be dealt out. 

 I congratulate you on this. 



We have heard of thee 



"zeal 

 Which young and ardent converts feel" ; 



and on thinking over the matter since, I am still of opinion that 

 you will do better not to have recourse to so low a mean winter 

 temperature as you have named. 



There is a difficulty in the river theory, in placing the terrace 

 gravel of St Acheul with that at Menchecourt, unless you sup- 

 pose that all at that place belongs to the second or lower valley 

 gravel. I do not see any objection to this, but I know that such 

 was not your notion at one time. Hooker was mightily taken 

 with the speculation as to the ice-hatchets, but I must confess 

 that I do not like it. As perhaps this offspring may be a 

 favourite, I will not ask you to discard it, but I think that if 

 you mentioned it in a footnote it would be enough. 



I would examine into the question of the Dreissena polymorpha. 

 I have no doubt but that the shell will turn out to be a D. 

 Brardii washed out from the upper Paris Basin beds, where 

 it is often most abundant. In the Mainz basin it is washed into 

 the alluvia of the Ehine. Yours ever truly, 



EGBERT GODWIN- AUSTEN. 



The first note-book entry for 1862 is, "Easter Ex- 

 cursion, 17th April : J. Evans, J. Lubbock, J. P. 



" Route. St Valery, Abbeville, Beauvais, Rouen, 

 Nantes, Poissy, Paris, Creil, Amiens ; back on Monday 

 morning the 28th inst." 



Although only one geological memoir proceeded from 

 his pen in this year, there was another publication 



