The Wallace-Darwin Correspondence 



Waldron Edge, Duppas Hill, Croydon. January 9, 1880. 



My dear Darwin,— It is a great pleasure to receive a 

 letter from you sometimes— especially when we do not 

 differ very much. I am, of course, much pleased and 

 gratified that you like my article. I wrote it chiefly because 

 1 thought there was something a little fresh still to say on 

 the subject, and also because I wished to define precisely 

 my present position, which people continually misunder- 

 stand. The main part of the article forms part of a chap- 

 ter of a book I have now almost finished on my favourite 

 subject of ** Geographical Distribution. '' It will form a 

 sort of supplement to my former work, and will, I trust, 

 be more readable and popular. I go pretty fully into the 

 laws of variation and dispersal; the exact character of 

 specific and generic areas, and their causes; the growth, 

 dispersal and extinction of species and groups, illustrated 

 by maps, etc. ; changes of geography and of climate as affect- 

 ing dispersal, with a full discussion of the Glacial theory, 

 adopting CrolFs views (part of this has been published as 

 a separate article in the Quarterly Review of last July, 

 and has been highly approved by Croll and Geikie) ; a dis- 

 cussion of the theory of jiermanent continents and oceans, 

 which I see you were the first to adopt, but which geologists, 

 I am sorry to say, quite ignore. All this is preliminary. 

 Then follows a series of chapters on the different kinds of 

 islands, continental and oceanic, with a pretty full discus- 

 sion of the characters, affinities, and origin of their fauna 

 and flora in typical cases. Among these I am myself quite 

 pleased with my chapters on New Zealand, as I believe I 

 have fully explained and accounted for all the main pecu- 

 liarities of the New Zealand and Australian floras. I call 

 the book '' Island Life,'' etc. etc., and I think it will be 



interesting. 



305 



