frondescent

Updated: May 12, 2025

Calcareous deposits and frondescent incrustations on the coast. Remarkable laminated beds, alternating with, and passing into, obsidian. Origin of obsidian. Lamination of volcanic rocks. The whole is volcanic, and, from the absence of proofs to the contrary, I believe of subaerial origin. The fundamental rock is everywhere of a pale colour, generally compact, and of a feldspathic nature.

Charles Darwin - Volcanic Islands