Urges CD to visit Flores Island near Montevideo if he has not already done so. Describes formation of greenstone and the granite formations on small islands in the Uruguay channel.

Sends specimens from Pôrto Alegre [Brazil] for identification by CD.

Thanks CD for letter of 5 April and specimens; did not know the Falklands and Patagonia were so interesting geologically.

Will answer CD’s queries about S. Brazil in another letter. Names Friedrich Sellow, A. Saint-Hilaire, and Andrew Mathews as naturalists who travelled there. Directs CD to Alexander Caldcleugh in Santiago.

Sends some geological specimens. Describes his recent trips and findings on the geology of the Andes. Asks if HSF has seen large beds of shells on elevated land – possibly at Rio Grande or S. Brazil.