Discusses theory of submerged continental extensions. Objects that if it is applied to one island, it must be applied to all. Admits that some volcanoes may have been associated with subsidence, in contrast to his former view. Cites evidence from S. American Cordillera. Doubts that elevation associated with volcanoes is merely local, and that great ocean areas are necessarily sinking.

Says he will make his essay [on species] as complete as possible and will discuss CL’s Principles.