u for it.

LETTER 390. FROM A.R. WALLACE TO CHARLES DARWIN. The Dell, Grays, Essex,
June 7th, 1876.

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 page 184 of Volume 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 conclusion
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 Volume I., pages 398-403, and 459-66. My
general conclusions as to distribution of land mollusca are at Volume
II., pages 522-9. (390/1. "Geographical Distribution" II., pages 524,
525. Mr. Wallace points out that "hardly a small island on the globe but
has some land-shells peculiar to it"--and he goes so far as to say that
probably air-breathing mollusca have been chiefly distributed by air-
or water-carriage, rather than by voluntary dispersal on the land.) 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 the 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.

I hope your health is improved; and when, quite at your leisure, you
have waded through my book, I trust you will again let me have a few
lines of friendly criticism and advice.

LETTER 391. TO A.R. WALLACE. Down, June 17th, 1876.

I have now finished the whole of Volume I., with the same interest and
admiration as before; and I am convinced that my judgment was right
and that it is a memorable book, the basis of all future work on the
subject. I