d down; and...during the elevatory
movements there is but a small chance of durable fossiliferous deposits
accumulating" (loc. cit., page 139).)

Chapter VI.--Perhaps some facts on metamorphism, but chiefly on the
layers in mica-slate, etc., being analogous to cleavage.

Chapter VII.--The grand up-and-down movements (and vertical silicified
trees) in the Cordillera: see summary, page 204 and page 240. Origin of
the Claystone porphyry formation, page 170.

Chapter VIII., page 224.--Mixture of Cretaceous and Oolitic forms (page
226)--great subsidence. I think (page 232) there is some novelty in
discussion on axes of eruption and injection. (page 247) Continuous
volcanic action in the Cordillera. I think the concluding summary (page
237) would show what are the most salient features in the book.

LETTER 557. TO C. LYELL. Shrewsbury [August 10th, 1846].

I was delighted to receive your letter, which was forwarded here to
me. I am very glad to hear about the new edition of the "Principles,"
(557/1. The seventh edition of the "Principles of Geology" was published
in 1847.), and I most heartily hope you may live to bring out half a
dozen more editions. There would not have been such books as d'Orbigny's
S. American Geology (557/2. "Voyage dans l'Amerique meridionale execute
pendant les Annees 1826-37." 6 volumes, Paris, 1835-43.) published, if
there had been seven editions of the "Principles" distributed in France.
I am rather sorry about the small type; but the first edition, my old
true love, which I never deserted for the later editions, was also in
small type. I much fear I shall not be able to give any assistance to
Book III. (557/3. This refers to Book III. of the "Principles"--"Changes
of the Organic World now in Progress.") I think I formerly gave my
few criticisms, but I will read it over again very soon (though I
am striving to finish my S. American Geology (557/4. "Geological
Observations on South America" was published in 1846.)) and see whether
I can give you any references. I have been thinking over the subject,
and can remember no one book of consequence, as all my materials (which
are in an absolute chaos on separate bits of paper) have been picked out
of books not directly treating of the subjects you have discussed, and
which I hope some day to attempt; thus Hooker's "Antarctic Flora" I have
found eminently useful (557/5. "Botany of the Antarctic Voyage of H.M.S.
'Erebus' and 'Terror' in the Years 1839-