Feels sure that at times the globe must have been superficially cooler. Believes CD will turn out right with regard to migration across the equator via mountain chains, while the tropical heat of certain lowlands was retained.

Surprised at Hooker’s introducing "so organic a change as a deviation in the axis of the planet" to explain the cold of the Glacial Period.

Comments on cool-period MS. Still believes geographical changes principal cause of former changes of climate.