Note 89 — Chapter XIV · DESCRIPTION OF THE GEOLOGICAL AND GENERAL PHYSICAL FEATURES (continued)

It displays an abundance of small phenocrysts of plagioclase, augite, and olivine partly serpentinised, in a groundmass composed in the main of coarse augite grains (·025 mm. in size) and of felspar microliths (·07 mm. in length) in smaller proportion, with little if any residual glass. Specific gravity 2·98. It is near the Waikawa basalt, referred to on p. 202, and is placed in the same genus (13) of the olivine class.