of the only conclusion which I can draw from
this fact, namely that there must have been a depression in the surface
of the land to that amount. But neglecting this consideration, it was a
most satisfactory support of my presumption of the Tertiary (I mean by
Tertiary, that the shells of the period were closely allied, or some
identical, to those which now live, as in the lower beds of Patagonia)
age of this eastern chain. A great part of the proof must remain upon my
ipse dixit of a mineralogical resemblance with those beds whose age
is known, and the character of which resemblance is to be subject
to infinite variation, passing from one variety to another by a
concretionary structure. I hardly expect you to believe me, when it is
a consequence of this view that granite, which forms peaks of a height
probably of 14,000 feet, has been fluid in the Tertiary period; that
strata of that period are altered by its heat, and are traversed by
dykes from the mass. That these strata have also probably undergone an
immense depression, that they are now inclined at high angles and form
regular or complicated anticlinal lines. To complete the climax and seal
your disbelief, these same sedimentary strata and lavas are traversed by
VERY NUMEROUS, true metallic veins of iron, copper, arsenic, silver and
gold, and these can be traced to the underlying granite. A gold mine has
been worked close to the clump of silicified trees. If when you see my
specimens, sections and account, you should think that there is
pretty strong presumptive evidence of the above facts, it appears
very important; for the structure, and size of this chain will bear
comparison with any in the world, and that this all should have been
produced in so very recent a period is indeed wonderful. In my own
mind I am quite convinced of the reality of this. I can anyhow most
conscientiously say that no previously formed conjecture warped my
judgment. As I have described so did I actually observe the facts. But I
will have some mercy and end this most lengthy account of my geological
trip.

On some of the large patches of perpetual snow, I found the famous red
snow of the Arctic countries; I send with this letter my observations
and a piece of paper on which I tried to dry some specimens. If the fact
is new and you think it worth while, either yourself examine them or
send them to whoever has described the specimens from the north and
publish a notice in any of the perio