Chapter 379

reference is to proof-sheets.), as usual, with great interest. The points are awfully intricate, almost at present beyond the confines of knowledge. The view which I should have looked at as perhaps most probable (though it hardly differs from yours) is that the whole world during the Secondary ages was inhabited by marsupials, araucarias (Mem.--Fossil wood so common of this nature in South America (345/2. See Letter 6, Note.)), Banksia, etc.; and that these were supplanted and exterminated in the greater area of the north, but were left alive in the south. Whence these very ancient forms originally proceeded seems a hopeless enquiry.

Your remarks on the passage of the northern forms southward, and of the southern forms of no kinds passing northward, seem to me grand. Admirable, also, are your remarks on the struggle of vegetation: I find that I have rather misunderstood you, for I feared I differed from you, which I see is hardly the case at all. I cannot help suspecting that you put rather too much weight to climate in the case of Australia. La Plata seems to present such analogous facts, though I suppose the naturalisation of European plants has there taken place on a still larger scale than in Australia...

You will get four copies of my book--one for self, and three for the foreign botanists--in about ten days, or sooner; i.e., as soon as the sheets can be bound in cloth. I hope this will not be too late for your parcels.

When you read my volume, use your pencil and score, so that some time I may have a talk with you on any criticisms.