irruption of a multitude of new inhabitants, or
by the final subsidence of an island, the extinction may have been
comparatively rapid."), it never occurred to me that you alluded to
extinction of marine life: an isthmus is a piece of land, and you go on
in the same sentence about "an island," which quite threw me out, for
the destruction of an isthmus makes an island!

I surely did not say Azores nearer to Britain and Newfoundland "than to
Madeira," but "than Madeira is to said places."

With regard to the Madeiran coleoptera I rely very little on local
distribution of insects--they are so local themselves. A butterfly is
a great rarity in Kew, even a white, though we are surrounded by market
gardens. All insects are most rare with us, even the kinds that abound
on the opposite side of Thames.

So with shells, we have literally none--not a Helix even, though they
abound in the lanes 200 yards off the Gardens. Of the 89 Dezertas
insects [only?] 11 are peculiar. Of the 162 Porto Santan 113 are
Madeiran and 51 Dezertan.

Never mind bothering Murray about the new edition of the "Origin" for
me. You will tell me anything bearing on my subject.

LETTER 369. J.D. HOOKER TO CHARLES DARWIN. Kew, August 7th, 1866.

Dear old Darwin,

You must not let me worry you. I am an obstinate pig, but you must not
be miserable at my looking at the same thing in a different light from
you. I must get to the bottom of this question, and that is all I can
do. Some cleverer fellow one day will knock the bottom out of it, and
see his way to explain what to a botanist without a theory to support
must be very great difficulties. True enough, all may be explained, as
you reason it will be--I quite grant this; but meanwhile all is not so
explained, and I cannot accept a hypothesis that leaves so many facts
unaccounted for. You say the temperate parts of N. America [are] nearly
two and a half times as distant from the Azores as Europe is. According
to a rough calculation on Col. James' chart I make E. Azores to Portugal
850, West do. to Newfoundland 1500, but I am writing to a friend at
Admiralty to have the distance calculated (which looks like cracking
nuts with Nasmyth's hammer!)

Are European birds blown to America? Are the Azorean erratics an
established fact? I want them very badly, though they are not of much
consequence, as a slight sinking would hide all evidence of that sort.

I do want to sum up impartially, leaving the verdict