Thanks Horner for his letter [about Volcanic islands].
Discusses craters of elevation with respect to the views of Leopold von Buch and Élie de Beaumont. Compares Lyell’s views to those of continental geologists. Mentions reading A. D. d’Orbigny [Voyage dans l’Amérique méridionale (1835–47)].
Encloses note from Emma to Mrs Horner, inviting the Horners to visit Down.