Wellington Philosoyhical Society. 737 



far as seen, Auckland Island is altogether volcanic, and closely resembles 

 the rock-structure of Banks Peninsula. The northern part recalls the 

 aspect of the country north of Waikouaiti, with conical hills formed by 

 denuded basaltic sheets ; but further south along ti)e east coast there is a 

 succession of hasbours or inlets like those in Banks Peninsula, the steep 

 shores of which are formed of successive sheets of ba-^altic lava, often 

 columnar, and varying from 10ft. to 80ft. in thickness. These are sepa- 

 rated by brightly coloured layers of volcanic tufa or ashes containing 

 interspersed blocks of all sizes. The lava-flows can be traced by the eye 

 to the highest peaks overlooking the west coast of the island, all dipping 

 eastward at from 5*^ to 10°, but at the north and south ends of the island 

 the slope is towards these directions. Along the west coast there are na 

 indentations, only precipitous cliffs, and one off-lying rock, " Disappoint- 

 ment Island," which is probably a "neck" or "dyke" through which 

 some of the igneous rocks have been extruded. Carnley Harbour divides 

 Adam's Island from tlie mainland, and appears to have been formed by a 

 dislocating east-and-west fault. The south side of Adam's Island is the 

 most exposed part of the Aucklands, and presents cliffs composed, as 

 exposed in section, of horizontal layers of basalt and tufa to a height of 

 1,900ft., some of the cliffs being 1, 400ft. sheer down. The lava-sheets 

 vary in thickness from 10ft. to 80ft., and there is evidence of not less 

 than seventy disinct outpourings still preserved above the sea-level. At 

 soundmg three miles off shore from the South Cape gave 95 fathoms 

 (575ft.). The average dip of the lava-floes to the eastward is 7°; the 

 width of tiie island in this section is ten miles, and the height of the 

 western cliffs 1,000ft. ; so that, by adopting the usually-accepted curve 

 for volcanic deposits, we have the following result : Auckland Island is 

 the remnant of a great volcanic cone that was 12,000ft. in height and 

 fifty miles in diameter in earl}' Tertiary times, the chief centre having 

 been about eight miles west of Disappointment Island. Four-fifths of 

 the original mass has been removed by the denuding force of the westerly 

 waves. 



3. Ccunpbell Island is a volcanic mass, but has the peculiar feature 

 of having slightly above the sea level the original rock-formation on 

 which it is founded. On the nortli and south it presents fantastic peaks 

 and precipices, carved out of rocks of the same character as those which 

 form Otago Peninsula. Towards the southern end it is traversed by 

 Perseverance Harbour east and west, which is by a moderately high 

 saddle connected with West Harbour. On the north and south of this 

 rift are frowning cliffs and peaks of basaltic lava-sheets; but at the sea- 

 level there is an exposure, both on the east and west coasts of the island, 

 of the Upper Cretaceous rocks, with chalk flints and fossil wood, such as 

 is found in New Zealand in tlie Upper Amuri series. These have been 

 brought to the surface-level together witli the volcanic outburst, as they 

 are injected and interstratified with dykes and tufa-rocks of the same 

 kind. The wonderful luystery of the occurrence of fossilised dicoty- 

 ledonous wood in the far south latitude of Campbell Island is therefore 

 throw-n entirely out of the distribution of plant-life in Tertiary times, and 

 must be referred to the Cretaceous epoch. At an altitude of 800ft. clear 

 evidence of the former existence of a true corrie and moraine of the first 

 order was obtained, but it is purely local, and is the only evidence of 

 former glacier action observed. 



4. Antipodes Island is the result of four distinct centres pouring out 

 scoria and basaltic lavas with enormous deposits of volcanic breccia, 

 whicli proves the great local violence of the eruptions. The erosion of the 

 coast line has been very slight considering the friable nature of the rock, 

 so that the eruptions must have occurred in a very late geological time, 

 coincident probably with those of the Auckland Peninsula. 



5. Chatham Islands have a very complex structure, the northern 

 47 



