if I am utterly floored.

P.S.--I have a presentiment it will turn out that when clay-slate has
been metamorphosed the foliation in the resultant schist has been due
generally (if not, as I think, always) to the cleavage, and this to a
certain degree will "save my bacon" (please look at my saving clause,
page 167) (542/2. "As in some cases it appears that where a fissile rock
has been exposed to partial metamorphic action (for instance, from
the irruption of granite) the foliation has supervened on the already
existing cleavage-planes; so, perhaps in some instances, the foliation
of a rock may have been determined by the original planes of deposition
or of oblique current laminae. I have, however, myself never seen such
a case, and I must maintain that in most extensive metamorphic areas the
foliation is the extreme result of that process, of which cleavage is
the first effect" (Ibid., page 167).), but [with] other rocks than that,
stratification has been the ruling agent, the strike, but not the dip,
being in such cases parallel to any adjoining clay-slate. If this be
so, pre-existing planes of division, we must suppose on my view of the
cause, determining the lines of crystallisation and segregation, and
not planes of division produced for the first time during the act of
crystallisation, as in volcanic rocks. If this should ever be proved, I
shall not look back with utter shame at my work.

LETTER 543. TO J.D. HOOKER. Down, September 8th [1856].

I got your letter of the 1st this morning, and a real good man you have
been to write. Of all the things I ever heard, Mrs. Hooker's pedestrian
feats beat them. My brother is quite right in his comparison of "as
strong as a woman," as a type of strength. Your letter, after what
you have seen in the Himalayas, etc., gives me a wonderful idea of the
beauty of the Alps. How I wish I was one-half or one-quarter as strong
as Mrs. Hooker: but that is a vain hope. You must have had some very
interesting work with glaciers, etc. When will the glacier structure
and motion ever be settled! When reading Tyndall's paper it seemed to me
that movement in the particles must come into play in his own doctrine
of pressure; for he expressly states that if there be pressure on all
sides, there is no lamination. I suppose I cannot have understood him,
for I should have inferred from this that there must have been movement
parallel to planes of pressure. (543/1. Prof. Tyndall had published
p