ion
this in case they should be stowed beneath geological specimens and thus
escape your notice, perhaps some spirit may be wanted in them. If a
box arrives from B. Ayres with a Megatherium head the other unnumbered
specimens, be kind enough to tell me, as I have strong fears for its
safety. We arrived here the day before yesterday; the views of the
distant mountains are most sublime and the climate delightful; after our
long cruise in the damp gloomy climates of the south, to breathe a clear
dry air and feel honest warm sunshine, and eat good fresh roast beef
must be the summum bonum of human life. I do not like the look of
the rocks half so much as the beef, there is too much of those rather
insipid ingredients, mica, quartz and feldspar. Our plans are at present
undecided; there is a good deal of work to the south of Valparaiso and
to the north an indefinite quantity. I look forward to every part with
interest. I have sent you in this letter a sad dose of egotism, but
recollect I look up to you as my father in Natural History, and a son
may talk about himself to his father. In your paternal capacity as
proproctor what a great deal of trouble you appear to have had. How
turbulent Cambridge is become. Before this time it will have regained
its tranquillity. I have a most schoolboy-like wish to be there,
enjoying my holidays. It is a most comfortable reflection to me, that
a ship being made of wood and iron, cannot last for ever, and therefore
this voyage must have an end.

October 28th. This letter has been lying in my portfolio ever since
July; I did not send it away because I did not think it worth the
postage; it shall now go with a box of specimens. Shortly after arriving
here I set out on a geological excursion, and had a very pleasant ramble
about the base of the Andes. The whole country appears composed of
breccias (and I imagine slates) which universally have been modified and
oftentimes completely altered by the action of fire. The varieties of
porphyry thus produced are endless, but nowhere have I yet met with
rocks which have flowed in a stream; dykes of greenstone are very
numerous. Modern volcanic action is entirely shut up in the very central
parts (which cannot now be reached on account of the snow) of the
Cordilleras. In the south of the R. Maypu I examined the Tertiary
plains, already partially described by M. Gay. (5/3. "Rapport fait a
l'Academie Royale des Sciences, sur les Travaux Geologiques de M.