36

32 THE GEOLOGY OF AUCKLAND.

stretches in a more northerly direction to the East Coast,
between Maketu and Tauranga, the farthest extremities of
which reach even to the Auckland District. On one side of
Hauraki Gulf, the Coromandel range is covered with trachytic
breccia, and again, on the West Coast, the same rock forms the coast-
range from Manukau to Kaipara. This extensive plateau is
intersected by many deep valleys, the sides of which are
characterised by a succession of remarkable terraces. The same
plateau is also broken in many places by more or less regular
trachytic cones from 1000 to 3000 feet high. That you may
become acquainted with the geological character of such moun-
tains, I will mention several examples, the names of which are
well known amongst European settlers. To this class of moun-
tains belong Karioi on the West Coast, near Whaingaroa,
Pirongia or the Waipa, the regular cone of Kakepuku between
the Waipa and the Waikato, Maungatautari on the Waikato,
Aroha on the Waihou, Putauaki or Mount Edgecombe on the
East Coast, and many others. The only active mountain which
belongs to this class is Whakari or White Island, in the Bay of
Plenty, a solfatara like the active crater of Tongariro.

Mr David Burn, in his account of "A Trip to the East
Cape," says:-

"In about an hour after passing Flat Island, the snowy
vapour upon White Island began to be discernible. By 1 p.m.
we were in immediate contiguity with this remarkable island,
passing quite close to its southern extremity. As we made our
gradual approach, its aspect was of the most singular description.
Except on its northern point, to which the sulphurous vapour
does not seem to reach, it is utterly destitute of vegetation;
there are patches of growing underwood; but in every other
direction, the island is bald, bleak, and furrowed into countless
deep-worn ravines. After we had passed it a short distance to
the eastward, the capacious basin of the crater, with its nume-
rous geysers roaring and raging, exposed its sulphurous bosom
to our eyes and nostrils. If the outer and western sides of
White Island be blank and furrowed, its inner circle is chased,
as it were, in a rare and picturesque manner - the sides of the
hills, from their lofty mountain summits to the base, being