nd much more carbonic acid than the
higher plants, the hypothesis seems to me far too rash. Saporta believes
that there was an astonishingly rapid development of the high plants,
as soon [as] flower-frequenting insects were developed and favoured
intercrossing. I should like to see this whole problem solved. I
have fancied that perhaps there was during long ages a small isolated
continent in the S. Hemisphere which served as the birthplace of the
higher plants--but this is a wretchedly poor conjecture. It is odd
that Ball does not allude to the obvious fact that there must have
been alpine plants before the Glacial period, many of which would have
returned to the mountains after the Glacial period, when the climate
again became warm. I always accounted to myself in this manner for the
gentians, etc.

Ball ought also to have considered the alpine insects common to the
Arctic regions. I do not know how it may be with you, but my faith in
the glacial migration is not at all shaken.

LETTER 396. A.R. WALLACE TO CHARLES DARWIN.

(396/1. This letter is in reply to Mr. Darwin's criticisms on Mr.
Wallace's "Island Life," 1880.)

Pen-y-Bryn, St. Peter's Road, Croydon, November 8th, 1880.

Many thanks for your kind remarks and notes on my book. Several of the
latter will be of use to me if I have to prepare a second edition, which
I am not so sure of as you seem to be.

1. In your remark as to the doubtfulness of paucity of fossils being due
to coldness of water, I think you overlook that I am speaking only of
water in the latitude of the Alps, in Miocene and Eocene times, when
icebergs and glaciers temporarily descended into an otherwise warm sea;
my theory being that there was no Glacial epoch at that time, but merely
a local and temporary descent of the snow-line and glaciers owing to
high excentricity and winter in aphelion.

2. I cannot see the difficulty about the cessation of the Glacial
period.

Between the Miocene and the Pleistocene periods geographical changes
occurred which rendered a true Glacial period possible with high
excentricity. When the high excentricity passed away the Glacial epoch
also passed away in the temperate zone; but it persists in the arctic
zone, where, during the Miocene, there were mild climates, and this
is due to the persistence of the changed geographical conditions. The
present arctic climate is itself a comparatively new and abnormal state
of things, due to geographical modifica