Discusses J. D. Dana’s Geology [1849]. Pleased that the part on corals confirms his views [Coral reefs (1842)]. Discusses Dana’s observation that in Sandwich Islands lava streams often join dikes at right angles with no cone. Retracts earlier denial of this possibility. Criticises Dana’s view of Australian valleys.

Continues discussion of Dana’s Geology [1849]. Comments on dikes of Hawaiian volcanoes and Dana’s view of craters of denudation. Compares role of sea and rivers in forming valleys. Criticises Dana’s treatment of CD’s account of coral reefs.

Comments on AC’s experiments on Phlox and Mimulus.

Discusses the new genus, Alcippe, described by AH ["Notice of the occurrence on the British coast of a burrowing barnacle", Ann. & Mag. Nat. Hist. 2d ser. 4 (1849): 305–14]. Comments on Lithotrya, Clitia, and Anatifa. Discusses cirripede larvae. Asks which Mollusca specimens AH wishes to borrow.