222 
TIIE GEOLOGY OF NEW ZEALAND. 
The surrounding plain of Taiamai, is covered with scoria 
and large masses of rock, which have, evidently, been ejected 
from some of the many neighbouring craters. There are also 
large quantities of vesicular iron, the pores of which appear to 
have been filled up with pipe-clay mud. 
Near Pa Karaka 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 subterraneous 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,liavingatitsbaseafinelakecalled Mapere. On theopposite 
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 remarkable 
apertures of great depth, through which, doubtless, the hot 
water was ejected; at the base are innumerable chasms of 
considerable depth, from some of which gas still escapes. 
Lava streams and basaltic rocks abound in all this 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 contains incontestable proofs of fearful dis¬ 
ruptions 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 
subterraneous lava passages,* and partial subsidings, which 
they simply scoop out a little hollow in the sand, about a foot deep, lining it 
with old mats, upon which the patient is placed with a blanket thrown over 
the person to keep in the heat. The invalids generally remain about a month 
at the baths, and have little temporary huts erected, which give a singular 
appearance to this lonely and desolate region. 
* Those called the “ Three Kings,” in particular, are well worth the Geolo¬ 
gist’s attention; they are evidently subterraneous lava courses; in some places 
