280
THE NEW ZEALAND GAZETTE.

in this volcanic region in the Hanmer
Plains,* at the foot of the Kaikoras.

Specimens forwarded to me by gentlemen,
some from the Kaikoras, and some boulders
from the Awatere, prove that the princi-
pal rocks in this district are basaltic and tra-
chytic lavas.

Following the southerly direction indi-
cated by the relative position of the two
Kaikora groups, we come next to Banks'
Peninsula, undoubtedly an extinct volcanic
system, rising like an island out from the
sea and level plains.

In the same line farther south, lies a third
group of volcanic hills, forming the penin-
sula at Otago.

These three points doubtless indicate a
line of volcanic action, running parallel to
the great middle range or backbone of the
Middle Island, on the eastern side of it.

A closer examination, especially of the Otago
province, would no doubt furnish us with
more and similar examples of volcanic hills
on that line. It is remarkable that, whilst
the parallel zones of volcanic action on the
Northern Island—the Tongariro zone, the
Auckland and the Bay of Islands zone—all
run on the western side of the backbone
range between Wellington and the East
Cape; the great volcanic line of the Mid-
dle Island takes the eastern side.

Many peculiarities in the physical features
of the Middle Island, and also many inter-
esting facts respecting the earthquakes in
New Zealand, can be explained by the differ-
ent position of the line of volcanic action
in the two islands.

Reserving, however, for my future publi-
cations this interesting subject, which, I
regret, I have not time now to enter upon, I
will, in conclusion, offer a few

GENERAL REMARKS.

In the earlier geological era of New Zea-
land, we may assume that both islands
were connected, and that one backbone ran
continuously from the S. Cape to the E. Cape.

*At this house (Top house) I met some gentlemen
newly arrived and stopped on their road by the river
had made the journey from Port Cooper, and he
gave me an account of hot springs which he had dis-
covered on the Hanmer Plains, under the shelter of a
range of snow hills. He observed what seemed to him
a remarkable fog, and upon leaving his track to ex-
amine, he discovered some holes, which were filled
with water of a temperature varying from milk warm
to almost boiling. The largest of them contained the
hottest spring, and although he attempted to sound
the depth with all the rope he could procure, he was
unable to find the bottom. The circumference of the
largest was about fifteen or eighteen yards. This is
I believe, the only instance of hot-springs yet dis-
covered in the Middle Island, and, if corroborated, may
tend to throw some light on the volcanic connection
between this district and the Northern Island..." A
Walk from the Wairau," from the Nelson Examiner,
May 25, 1859.

In the present map of New Zealand the
integrity of this backbone is broken at Cook
Strait, and a closer inspection will show
that there has been not only a simple break
of continuity, but, a lateral dislocation.
Cook Strait is, to use a miner's expression, a
bone fault. It is evident from the rocks
being of the same geological formation, that
at one period the Pelorus ranges were a
continuation of the Wellington ranges.
The position of the strata in the eastern
ranges of Nelson prove, that whilst the
Northern Island seems to have remained sta-
tionary, some gigantic force has pressed the
great mass of the Middle Island to the
westward. The given description of the
tertiary formation, extending between the
ranges far up the valleys, sounds and bays
leading towards Cook Strait on both sides,
farther proves that the first act of this
great convulsion of nature took place prior
to the tertiary period, and the second, and
subsequent acts, may be coeval with the
period of volcanic action in the Islands.

While the tertiary sea was depositing in
the strata which now fill the valleys, and
which rise in some parts to an altitude of
2000 feet, the higher ranges of New Zea-
land only were above water.

Since the tertiary period, these Islands
have been gradually rising, and that
rising has been coeval with the vol-
canic action, and developed to the great-
est amount along the zones of volcanic
action. It was in this time that the exten-
sive plains on the east coast of the middle
Island, and the plateaus on the western side
of the northern backbone, were raised above
the sea. The best proof of this rising of
the land is to be found in the river terraces,
which strike the eye of every traveller in the
valleys of the Wairau, Awatere, Clarence,
Motueka, Wangapeka, Buller, Takaka, and
Aorere, and also in the lines of the sandy
downs on the Port Cooper Plains, which now,
miles inland, mark the former limit of the
sea.

These terraces are formed by the gradual
rise of the land. If we suppose that, while
the rivers are shaping out their beds, the up-
heaving movement is intermittent, so
that long pauses occur, during which
the stream will have time to encroach
upon one of its banks, so as to clear
away and flatten a large space, this
operation being repeated at lower levels,
there will be several successive cliffs and ter-
races. It is remarkable that in all the val-
leys the cliffs of the higher terraces are of a
greater altitude than the lower. At the Bul-
ler River, for example, near its outlet from
the Rotoiti lake, the uppermost cliff is 100
feet in height, and there can be distinguished