or ever. You have written, as I believe, a grand
and memorable work, which will last for years as the foundation for all
future treatises on Geographical Distribution,--My dear Wallace, yours
very sincerely,

CHARLES DARWIN.

P.S.--You have paid me the highest conceivable compliment by what you
say of your work in relation to my chapters on Distribution in the
"Origin," and I heartily thank you for it.

* * * * *

_The Dell, Grays, Essex. June 7, 1876._

Dear Darwin,--Many thanks for your very kind letter. So few people will
read my book at all regularly, that a criticism from one who does so
will be very welcome.

If, as I suppose, it is only to p. 184 of Vol. I. that you have read,
you cannot yet quite see my conclusions on the points you refer to (land
molluscs and Antarctic continent). My own conclusions fluctuated during
the progress of the book, and I have, I know, occasionally used
expressions (the relics of earlier ideas) which are not quite consistent
with what I say further on. I am positively against any Southern
continent as _uniting_ South America with Australia or New Zealand, as
you will see at Vol. I., pp. 398-403 and 459-466. My general conclusions
as to Distribution of Land Mollusca[101] are at Vol. II., pp. 522-529.
When you have read these passages and looked at the general facts which
lead to them, I shall be glad to hear if you still differ from me.

Though, of course, _present results_ as to origin and migrations of
genera of mammals will have to be modified owing to new discoveries, I
cannot help thinking that much will remain unaffected, because in all
geographical and geological discoveries the great outlines are soon
reached; the details alone remain to be modified. I also think much of
the geological evidence is now so accordant with, and explanatory of,
geographical distribution that it is prima facie correct in outline.
Nevertheless, such vast masses of new facts will come out in the next
few years that I quite dread the labour of incorporating them in a new
edition.

Now for a little personal matter. For two years I have made up my mind
to leave this place--mainly for two reasons: drought and wind prevent
the satisfactory growth of all delicate plants; and I cannot stand being
unable to attend evening meetings and being obliged to refuse every
invitation in London. But I was obliged to stay till I had got it into
decent order to attract a customer.