Crystallisation favoured by space.
Dartigues, M., on sphaerulites.
Daubeny, Dr., on a basin-formed island. -on fragments in trachyte.
D’Aubuisson on hills of phonolite. -on the composition of obsidian. -on the lamination of clay-slate.
De la Beche, Sir H., on magnesia in erupted lime. -on specific gravity of limestones.
Denudation of coast at St. Helena.
Diana’s Peak, St. Helena.
Dieffenbach, Dr., on the Chatham Islands.
Dikes, truncated, on central crateriform ridge of St. Helena. -at St. Helena; number of; coated by a glossy layer; uniform thickness of. -great parallel ones at St. Helena. -not observed at Ascension. -of tuff. -of trap in the plutonic series. -remnants of, extending far into the sea round St. Helena.
Dislocations at Ascension. -at St. Helena.