Looks forward to the paper on CD’s edible fungus specimen from Tierra del Fuego [read 16 Mar 1841; Trans. Linn. Soc. Lond. 19 (1845): 37–43].

Sends a correction: Fagus betuloides, not F. antarctica, is the common tree of Tierra del Fuego.

Discusses the role of ice in determining the geological features of the Jura. Mentions view of Agassiz. Objects to idea of "a [sea of ice] carrying rocks". Notes Agassiz’s earlier view of "ice expanded in the line of the Great Swiss Valley". Comments on Pentlands.

Has enjoyed reading LA’s book [Études sur les glaciers (1840)].

Hopes LA will pardon manner in which CD has alluded to his work on glaciers in his Journal of researches, of which he sends a copy.

Defends his theory [in "Parallel roads of Glen Roy" (1839), Collected papers 1: 87–137] against the view that the "roads" were formed by glacial action.

Discusses at length Louis Agassiz’s book [Études sur les glaciers (1840)] and Agassiz’s explanation of moraines. Defends his own theory of the importance of floating ice. Relates glacier theory to his own interpretation of Glen Roy.

Mentions a paper he is writing on South American boulders and till [Collected papers 1: 145–63].

The Smith, Elder & Co. account for the now published fifth number of the third part of the Zoology is presented.