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APPENDIX, No. III.
GEOLOGY OF NEW ZEALAND. BY ROBERT McCORMICK, ESQ., SURGEON OF H. M. S. EREBUS.
My observations on the geological structure of this new colony were limited chiefly to the northern portion of the North Island, the Bay of Islands, and its vicinity.
The bay, perhaps, the finest harbour in New Zealand, is studded with several islands, and has its shores bounded by argillaceous cliffs of moderate height. The clay of which these are composed is of a yellow colour, variegated by a reddish tint, and rests upon a substratum of trappean rocks, fragments of which, more especially greenstone, frequently occur imbedded in it. A low tract of prismatic basalt, intermingled with scoriæ and greenstone, extends between the Waitangui and Kiddi-Kiddi (or, as it is also called, Keri-Keri) rivers. This, doubtless, has been a lava current, the source from whence it flowed being pretty clearly indicated by a conical crateriform hill, situated at no great distance inland of it. Several rivers fall into the bay, whose shore is intersected by numerous ravines, creeks, and mangrove swamps, Manawa (Avicennia tomentosa). Whilst the Expedition remained in the bay, the Manuka, or tea shrub of the New Zealanders (Leptospermum scoparium) was in full flower, and lent a cheerful appearance to the sides of the hills, over which it was spread in profusion; the paths of the natives leading in an intricate maze of windings through it around every neighbouring hill. That beautiful tree the Pohutukava (Metrosideros tomentosa) was just beginning to put forth its rich crimson blossoms, amid a deep green clustering foliage; and it appeared to be the favourite station of the
