Skeleton Islands of New Zealand and elsewhere

Abstract

Skeleton Islands are a variety of the class of islands resulting from subsidence of dissected land, subcategory 4a of a classification of islands here offered. Such islands are characterised by development of a sprawling outline with a narrow axial ridge from which slender lateral spurs, or ribs, extend more or less at right angles. Extreme skeletonisation is associated with development before a final drowning, or redrowning, of amphitheatre heads in valleys already heading in the main divide. This may be a climatically induced change of the valley form related, in the case of the New Zealand example, Arapawa Island, to cryergic (periglacial) activity in the Pleistocene glacial ages. Kakeroma Island (Ryukyu Group), an example of a skeleton island described by W. M. Davis, has quite possibly a history different from that of Arapawa Island as regards both the development of the relief of the subsiding lands and. being in a low latitude, the possibly climatic process responsible for shaping its now submerged valley heads and thus emaciating the ribs of the island.