t Mrs. Huxley keeps up pretty well. The work
which most men have to do is a blessing to them in such cases as yours.
God bless you.

Sir H. Holland came here to see her, and was wonderfully kind.

LETTER 351. TO C. LYELL. Down, November 20th [1860].

I quite agree in admiration of Forbes' Essay (351/1. "Memoir of the
Geolog. Survey of the United Kingdom," Volume I., 1846.), yet, on my
life, I think it has done, in some respects, as much mischief as good.
Those who believe in vast continental extensions will never investigate
means of distribution. Good heavens, look at Heer's map of Atlantis!
I thought his division and lines of travel of the British plants very
wild, and with hardly any foundation. I quite agree with what you say
of almost certainty of Glacial epoch having destroyed the Spanish
saxifrages, etc., in Ireland. (351/2. See Letter 20.) I remember well
discussing this with Hooker; and I suggested that a slightly different
or more equable and humid climate might have allowed (with perhaps some
extension of land) the plants in question to have grown along the entire
western shores between Spain and Ireland, and that subsequently they
became extinct, except at the present points under an oceanic climate.
The point of Devonshire now has a touch of the same character.

I demur in this particular case to Forbes' transportal by ice. The
subject has rather gone out of my mind, and it is not worth looking to
my MS. discussion on migration during the Glacial period; but I remember
that the distribution of mammalia, and the very regular relation of the
Alpine plants to points due north (alluded to in "Origin"), seemed to
indicate continuous land at close of Glacial period.

LETTER 352. TO J.D. HOOKER. Down, March 18th [1861].

I have been recalling my thoughts on the question whether the Glacial
period affected the whole world contemporaneously, or only one
longitudinal belt after another. To my sorrow my old reasons for
rejecting the latter alternative seem to me sufficient, and I should
very much like to know what you think. Let us suppose that the cold
affected the two Americas either before or after the Old World. Let
it advance first either from north or south till the Tropics became
slightly cooled, and a few temperate forms reached the Silla of Caracas
and the mountains of Brazil. You would say, I suppose, that nearly all
the tropical productions would be killed; and that subsequently, after
the cold ha