Discusses Louis Agassiz’s theory of the glaciation of Brazil.

Discussion of Mrs Agassiz’s letter [to Mary Lyell, forwarded to CD] regarding S. American glacial action,

with comments on Bunbury’s letter on temperate plants.

Refers to opinions of Agassiz, David Forbes, Hooker, and CD on glacial period and glaciers.

Wishes he had published a long chapter on glacial period [Natural selection, pp. 535–66] written ten years ago.

Tells of death of his sister, Catherine, and other family matters.

Thanks CL for Hooker’s letter.

Discussion of Hooker’s views on glacial action and temperature with specific reference to S. America.

His squabbles with Hooker on transport of seeds via water currents,

temperate plants, and preservation of tropical plants during cooler period.

Expresses interest in seeing Agassiz’s letter.

Discusses CD’s and J. D. Hooker’s letters to Lyell concerning Louis Agassiz’s theory of the glaciation of the Amazon basin in Brazil.

Comments on errors [in Origin] pointed out in C. J. F. Bunbury’s letters.

Mentions CD’s notes on Drimys, Fuchsia, and fossil mammals of Brazilian caves.

Sorrowful that his work must be put aside because Murray wants a new [4th] edition of Origin. Remarks on changes to be made regarding Organ Mountains and Agassiz’s glacial markings.

Has returned memorial to Chancellor of Exchequer; thanks CL for his note.

Lengthy remarks on cool period. Did not know of CL’s interest. New facts in new German and English [4th] editions of Origin will be too late for CL’s use. CD’s ten-year-old MS on cool period is available.

Gives details of enclosed MS on cool period. Mentions Hooker’s opposed "axis of the earth" view. Causes of glacial period are beyond CD; "cannot believe change in land and water being more than a subsidiary agent".

Disappointed to put off CL’s visit because of illness of CD’s sister [Susan], but hopes to see him in October.

Thanks for lending pamphlet [L. Agassiz, Geology of the Amazons]. Agassiz has written "wild nonsense".

Refers to a translation of Pictet and Humbert’s "capital" paper on fossil fish ["Recent researches on the fossil fishes of Mount Lebanon", Ann. & Mag. Nat. Hist. 3d ser. 18 (1866): 237].

Hooker’s lecture at BAAS Nottingham meeting.

Comments on the relationship between the plane of the earth's orbit and the obliquity of the ecliptic.

Comments on proofs [of Principles of geology, 10th ed. (1867–8)]: CL does not allude to the specialisation of classes.

Discusses CL’s argument from the absence of Cetacea in Secondary rocks;

finds his discussion of man "superfluous and too orthodox".

More comments on proofs [of CL’s Principles of geology, 10th ed.]. Discusses permanence of continents and other points.

Refers to passage describing evaporation of snow in Journal [of researches, pp. 277–8].

Cites astronomers’ views on increasing length of day.

Comments on some of CL's writings; further argues that a canal at Suez and/or Darien would have a major effect on European climate due to the effect of ocean currents coming through such canals.

Some minor suggestions regarding CL's proofs [see CL's 1866-10-19].

CD asks if he can call tomorrow (Friday) at 9: 30, and offers to come on Saturday if that would suit CL better.

Thanks CL for copy of his "grand book" [Principles of geology, 10th ed., vol. 1 (1867)]. Congratulates him on additions.

Appreciates the receipt of volume one of the tenth edition of CL's Principles of Geology.