may, perhaps, overlook the evidence on the opposite side; but
in the Alps the igneous alteration of the rocks, and the modes of their
upheaval, seem to me subjects of intense difficulty and mystery, and as
such Saussure always treats them; the evidence for the original
_deposition_ by water of the slaty crystallines appears to him, as it
does to me, often perfectly distinct.

Now, Saussure's universal principle was exactly the one on which I have
founded my account of the slaty crystallines:--"Fidele a mon principle,
de ne regarder comme des couches, dans les montagnes schisteuses, que
les divisions paralleles aux feuillets des schistes dont elles sont
composees."--_Voyages_, Sec. 1747. I know that this is an arbitrary, and in
some cases an assuredly false, principle; but the assumption of it by De
Saussure proves all that I want to prove,--namely, that the beds of the
slaty crystallines are in the Alps in so large a plurality of instances
correspondent in direction to their folia, as to induce even a cautious
reasoner to assume such correspondence to be universal.

The next point, however, on which I shall be opposed, is one on which I
speak with far less confidence, for in this Saussure himself is against
me,--namely, the parallelism of the beds sloping under the Mont Blanc.
Saussure states twice, Sec.Sec. 656, 677, that they are arranged in the form
of a fan. I can only repeat that every measurement and every drawing I
made in Chamouni led me to the conclusions stated in the text, and so I
leave the subject to better investigators; this one fact being
indisputable, and the only one on which for my purpose it is necessary
to insist, that, whether in Chamouni the beds be radiant or not, to an
artist's eye they are usually parallel; and throughout the Alps no
phenomenon is more constant than the rounding of surfaces across the
extremities of beds sloping outwards, as seen in my plates +37+, +40+,
and +48+, and this especially in the most majestic mountain masses.
Compare De Saussure of the Grimsel, Sec. 1712: "Toujours il est bien
remarquable que ces feuillets, verticaux au sommet, s'inclinent ensuite,
comme a Chamouni, contre le dehors de la montagne:" and again of the
granite at Guttannen, Sec. 1679: "Ces couches ne sont pas tout-a-fait
verticales; elles s'appuyent un peu contre le Nord-Est, ou, comme a
Chamouni, contre le dehors de la montagne." Again, of the "quartz
micace" of Zumloch, Sec. 1723: "Ces rochers sont