Canterbury and Westland. 357 



proximity, might be considered to be the continuation of the former, 

 which here flows down the steep side of the cinder cone. Gradually, 

 •as we retreat from the focus of eruption, the agglomerate beds 

 decrease in number and size, but they still are occasionally present 

 «ven close to the mouth of the tunnel near to the Heathcote entrance. 

 Some of them (as, for instance, No. 11, 11 chains from the Heathcote 

 end, Section No. 6), consist in their lower portion of fine ashes, or 

 lava d'aqua, and above of scoriae and lapilli, so as to suggest, that first 

 fine ashes had been thrown out or had been brought down the side in 

 the form of a mud stream, on the top of which large ejecta 

 were afterwards deposited. Another agglomerate bed having an 

 anticlinal or saddle arrangement is 22a, 17 to 20 chains from the 

 Lyttelton end. ; it was evidently deposited on the rim of the crater, 

 of which the uneven surface is well visible in its lower portion. After 

 its formation, two more agglomerate beds were deposited over it, 216 

 and 227, and 211 and 228 in the section, each being separated from 

 the other by a bed of laterite. Moreover, it is clear that, whatever 

 may have been its origin, the lowest portion of this and several other 

 agglomerate beds must have been deposited when in a state of high 

 temperature, as the argillaceous bed below it has been burnt red, so 

 as to take all the characteristics of a laterite. All round Banks' 

 Peninsula, agglomerate and ash beds are visible in the cliffs, but they 

 are like the lava streams of small vertical extent only, and we have to 

 approach more towards the centre of eruption, when we wish to see 

 them in their greatest dimensions. 



The largest and most numerous stony lava-streams are met with 

 towards the centre of the tunnel, where the basalt of which they are 

 composed possesses the greatest hardness and crystalline texture. 

 More towards the boundaries of the volcanic system, the lava-streams 

 are much thinner and, at the same time, more porphyritic, amygda- 

 loidal or scoriaceous, and it is very instructive to follow some of the 

 lava-streams which form clear sections in the deep valleys radiating 

 round the Peninsula, from the summit of the caldera wall to their 

 termination at its foot, and to note the gradual change in their size,, 

 and in the texture of the rocks of which they are composed. I have- 

 already alluded to the lava-stream 237, nine chains from the Lyttelton 

 end (Section No. 1), but in connection with it, I may here mention that 

 the first shaft sunk by Messrs. Smith and Knight, the English con- 

 tractors, unfortunately reached it soon below the surface of the 

 ground, and continued all the way through it to the roof of the tunnel. 



