Agrees that CD’s fossil shells do not differ from those ADd’O saw in South America. Apparent differences due to errors by G. B. Sowerby. Collection magnificent; recommends special publication. Enabled ADd’O to correct error in dating of sandstone of Concepción. Lists geological periods represented in collection from Jurassic to Diluvian. Collection includes unusual group of crepidules.

Identifications of CD’s fossil shells. New species marked; many described previously by ADd’O.

Encloses analysis of salt from Patagonia. Cannot account for its inferiority.

Previous letter [missing] on Edinburgh position was ill-tempered. Friends assure him that he ought to be thankful for opportunity to try for professorship.

Reports meeting with Humboldt in Paris.

Comments on G. B. Sowerby’s identifications of South American fossil shells [812]. [Notes from more than one original memorandum].

Comments on a compass diagram designed to show the dip, strike, and anticlinal lines of a geological formation.

Discusses cleavage planes of mineralogical specimens.

Regrets J. D. Hooker did not visit Berlin.

Describes legal difficulties of Ernst Dieffenbach.

Lists species of Infusoria found in dust samples. Discusses origin of Atlantic dust. Discusses Infusoria in cosmetic paint from Tierra del Fuego and Patagonian earth. Thanks CD for samples. Would like samples from sea-bed.

Discusses chemical reaction involving common salt and carbonate of lime.

Reports that he has an offer of an estate of about 325 acres that CD may find suitable.

JDH recommends Augustin de Saint-Hilaire’s Leçons de botanique [1841]. Relates opinions of European botanists on migration and plant distribution.

A Tasmanian Cyttaria is same species as CD’s Fuegian fungus. Did the species originate on the beeches of Fuegia or of Tasmania?

JDH gives interpretation of Vestiges.

John McCulloch, J. F. Schouw, and Lamarck on the species question.

First part of "Galapagos flora" ["Plants of the Galapagos Archipelago", Trans. Linn. Soc. Lond. 20 (1851): 163–233] finished but not printed.

Details of distribution of Galapagos flora. Peculiarity of island floras.

Leaves for Edinburgh on Wednesday.

Discusses the microscopic structure of rock samples from Chile and the Pampas. Describes organic remains found in the samples.

Has marked probable depths of the specimens on CD’s list of S. American shells. Asks for details which would provide more precise conclusions. [See South America, p. 226.]

Is about to send his paper on Galapagos beetles to press. Has written some introductory material on which he invites CD’s comments.

Discusses his paper on CD’s Galapagos beetles ["Coleopterous insects … in the Galapagos Islands", Ann. & Mag. Nat. Hist. 16 (1845): 19–41] which he will forward when printed. Has drawn up descriptions of several other insects from CD’s collections.

Answers CD’s questions relating to the flora of the Galapagos. [See 889.]

The translation of Humboldt’s Kosmos [Cosmos (1846–58)] is delayed.

Gives instances of peculiar genera with several good species in very small islands. Scarcity of insects on islands.

JDH cannot prove that there is much hybridising, but does not see why there should not be. "Bother variation, development & all such subjects, it is reasoning in a circle I believe after all."

On marking and shipment of fossils.

Has met the artist, J. M. Rugendas.

Discusses British and French relations with Rosas government [of Argentina].