Is mapping coral distribution on the Tortugas reef. His observations on the Florida peninsula suggest that it was built up from the debris of animal remains and was not elevated.

Responds to comments on geology of Florida.

Discusses coral reefs and paper by John Murray ["On the structure and origin of coral reefs and islands", Proc. R. Soc. Edinburgh 10 (1880): 505–18].

Comments on AA’s paper ["Paleontological and embryological development", Proc. Am. Assoc. Adv. Sci. 29 (1880): 389–414].

Discusses the structure and formation of the Florida peninsula. Part played by marine animals in building banks on which coral can thrive.

Thanks AA for letter on coral reefs. "I used to think … that areas of elevation and of subsidence must – as a general rule be separated by a single great line of fissure, or rather of several".

Suggests that AA urge again his views on reappearance of old characters.