But the Miocene and Eocene periods were
certainly warm, and these alpine plants could hardly have migrated over
tropical forest lands, while it is very improbable that if they had been
isolated at so remote a period, exposed to such distinct climatal and
organic environments as in Madagascar and Abyssinia, they would have in
both places retained their specific characters unchanged. The
presumption is, therefore, that they are comparatively _recent_
immigrants, and if so must have passed across the sea from mountain to
mountain, for the richness and speciality of the Madagascar forest
vegetation render it certain that no recent glacial epoch has seriously
affected that island.
Hoping that you are in good health, and wishing you the compliments of
the season, I remain yours very faithfully,
ALFRED R. WALLACE.
* * * * *
_Down, Beckenham, Kent. January 2, 1881._
My dear Wallace,--The case which you give is a very striking one, and I
had overlooked it in _Nature._[115] But I remain as great a heretic as
ever. Any supposition seems to me more probable than that the seeds of
plants should have been blown from the mountains of Abyssinia or other
central mountains of Africa to the mountains of Madagascar.
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