iod; the
Glacial shells are barely 1 per cent. extinct species. Multiply this by
the older Pliocene and Miocene epochs.

You also forget an author who, by means of atolls, contrived to submerge
archipelagoes (or continents?), the mountains of which must originally
have differed from each other in height 8,000 (or 10,000?) feet, so
that they all just rose to the surface at one level, or their sites are
marked by buoys of coral. I could never feel sure whether he meant
this tremendous catastrophe, all brought about by what Sedgwick called
"Lyell's niggling operations," to have been effected during the era of
existing species of corals. Perhaps you can tell me, for I am really
curious to know...(47/3. The author referred to is of course Darwin.)

Now, although there is nothing in my works to warrant the building up
of continents in the Atlantic and Pacific even since the Eocene period,
yet, as some of the rocks in the central Alps are in part Eocene, I
begin to think that all continents and oceans may be chiefly, if not
all, post-Eocene, and Dana's "Atlantic Ocean" of the Lower Silurian is
childish (see the Anniversary Address, 1856). (47/4. Probably Dana's
Anniversary Address to the "American Association for the Advancement of
Science," published in the "Proceedings" 1856.) But how far you are at
liberty to call up continents from "the vasty deep" as often as you
want to convey a Helix from the United States to Europe in Miocene or
Pliocene periods is a question; for the ocean is getting deeper of late,
and Haughton says the mean depth is eleven miles! by his late paper
on tides. (47/5. "On the Depth of the Sea deducible from Tidal
Observations" ("Proc. Irish Acad." Volume VI., page 354, 1853-54).) I
shall be surprised if this turns out true by soundings.

I thought your mind was expanding so much in regard to time that
you would have been going ahead in regard to the possibility of
mountain-chains being created in a fraction of the period required to
convert a swan into a goose, or vice versa. Nine feet did the Rimutaka
chain of New Zealand gain in height in January, 1855, and a great
earthquake has occurred in New Zealand every seven years for half
a century nearly. The "Washingtonia" (Californian conifer) (47/6.
Washingtonia, or Wellingtonia, better known as Sequoia. Asa Gray,
writing in 1872, states his belief that "no Sequoia now alive can
sensibly antedate the Christian era" ("Scientific Papers," II., page
144).)