To cast doubt on CD’s view that volcanic action is associated with elevation of land, CL suggests that local oscillations in strata underlying volcanoes could also explain how active volcanoes have uplifted fossil deposits of marine shells. Overall he is more inclined to believe that recent volcanoes belong to areas of subsidence rather than of elevation.

CD returns a letter from Wollaston.

Although opposed to the Forbesian doctrine [of continental extension] as a general rule, CD would have no objection to its being proved in some cases. Does not think Wollaston has proved it; nor can anyone until more is known about the means of distribution of insects – but the identity of the two faunas is certainly interesting.

His health is very poor and his "everlasting species-Book" quite overwhelms him with work. It is beyond his powers, but he hopes to live to finish it.

Response to Origin. Praise for summary of chapter 10 and chapter 11.

The dissimilarity of African and American species is ‘necessary result of “Creation” adapting new species to the pre-existing ones. Granting this unknown & if you please miraculous power acting’.

C. T. Gaudin writes of Oswald Heer’s finding many species common between Miocene floras of Iceland and Switzerland. Interesting for CD’s migration theory.

Wishes CD would enlarge on the doctrines of [Pyotr Simon] Pallas about the various races of dogs having come from several distinct wild species or sub-species.

Suggests organisms have a latent principle of improvement which is brought out by selection or breeding.

Since dogs have same gestation period as the wolf it is likely that the wolf is the ancestral wild species, if it is just one species.

CD’s belief that domestic dogs are descended from several distinct aboriginal species seems to contradict views on sterility of hybrids and variation in Origin. If domestic varieties came from hybrids of wild species it will be impossible to trace ancestry. Opponents will exploit these problems.

Questions CD’s view in Origin that domestic dogs are not descended from a single stock. Occasional crossings of domestic stock with wild species could explain cases of reversion towards wild specific forms. CD’s views on hybridity do not then have to be contradicted in constructing an ancestral stock.