THE GEOLOGY OE NEW ZEALAND. 
449 
where abounds, and resembles that of Taranaki, though of 
far larger and brighter grain. 
Near Pakaraka there is a remarkable volcanic cone, up- 
wards of four hundred feet high ; the mountain is hollow, 
and may be descended full three hundred feet, the sides are 
vitrified, and the small space at the bottom is covered with 
masses of rock and timber. At a little distance from the 
mountain there is a small lake whose surplus waters have a 
subterranean outlet, and from the neighbouring scoriaceous 
rock, gas is emitted in such quantities and force, that a 
bladder applied to one of the orifices may be easily filled. 
Pukenui is another extinct volcano in the same neighbour- 
hood, having at its base the fine lake Mapere ; on the opposite 
side rises a remarkable hill called Putai, formed entirely from 
the deposit of boiling springs, which once abounded there ; 
the mass of the hill is a soft, ochreous substance, filled with 
minute plates of mica ; on the top are several apertures of 
great depth, through which, doubtless, the hot water was 
ejected ; at the base also are innumerable deep chasms, from 
some of which gas still escapes ; lava streams and basaltic 
rocks abound throughout that region, clearly marking it as 
having once formed a grand centre of action, the range of 
which extended as far north as Wangaroa Harbour, which 
also exhibits incontestable proofs of fearful disruptions and 
upheavements. 
Passing on to the vicinity of Auckland, the attention is at 
once arrested by the number of ancient craters which arise 
from the surrounding plain. There are several remarkable 
subterranean lava passages,* and partial subsidings, which 
are well worth being noticed ; the lava, in many places, 
flowed under ground at such an inconsiderable depth, as to 
bake all the superincumbent soil to the consistency of brick, 
which contains many beautiful impressions of the leaves of 
* Those called the “Three Kings,” in particular, are well worth the geolo- 
gist’s attention ; they are evidently subterraneous lava courses ; in some places 
the pressure of the lava has caused the soil above to fall in, leaving wide aper- 
tures, by which the visitor now descends into them ; the natives formerly used 
them as places of sepulture. 
G G 
