324 Geology of 



CHAPTER XII. 



Backs' Peninsula. 



Hitherto I have not made any mention of Banks' Peninsula, beyond 

 alluding to the small zone of palaeozoic sedimentary rocks situated at 

 the head of Lyttelton Harbour, probably belonging to the Waihao 

 formation, of which a portion is considerably altered, and of another zone 

 in the same locality consisting of quartziferous porphyries, pitchstones, 

 rhyolites, and tufas, partly covering the former rocks. This chapter 

 will be devoted to a description of the geological features of that 

 remarkable volcanic zone as a whole, tracing its origin from the first 

 eruption of quartziferous porphyries and the deposition of tufas and 

 agglomerates in connection with them, to the extinction of the volcanic 

 foci by which it has been built up. 



"When standing on the Canterbury plains the most striking feature 

 in the landscape is Banks' Peninsula, rising so remarkably above the 

 sea horizon, that its regular form at once attracts our attention. 

 First we observe a series of mountains, of which the summits are all 

 nearly of the same altitude, which, as it appears to us, as far as our eye 

 can follow their outlines, form nearly a circle, from which a great 

 number of ridges slope with a nearly uniform gradient towards south, 

 west, and north. Above them, in the centre, stands conspicuously a higher 

 truncated mountain with precipitous escarpments, assuming, according 

 to the position of the traveller, a different aspect. The rim of the 

 lower mountains in front rises to an average height of 1600 feet, 

 whilst the central system attains an altitude of 3050 feet. On reaching 

 Banks' Peninsula from the sea, we find that several deep indentations, 

 forming splendid harbours, enter far into the outer rim of the moun- 



