38

34 THE GEOLOGY OF AUCKLAND.

was a fountain, seemingly of molten sulphur, in active play,
which shot a column of wide-spreading green and gold into the
scorching atmosphere. The beauty of this fountain was sur-
passing, and we were under the impression, that from its
energy, the volcano was more than commonly active in its
workings. We were very circumspect in our approaches, as
the surface in places was soft and yielding, and we knew not to
what brimstone depths an unwary step might sink us. Our
difficulty in walking, therefore, arose less from the heat, though
that in places was great, than from the apprehension of sinking
too far in the soft crustaceous surface, from which diminutive
spouts of vapour would spit forth as if to resent our intrusion.
Whenever we thought the ground at all doubtful, we sounded
our way by hurling large stones to see what impression the would
make, and we adventured or avoided proceeding accordingly.

"Time, to our great regret, would not admit of a minute
exploration, but all the grand features of the island had passed
under view. We looked in vain for the gorgeous meadow
described by Capt. Drury; but we had only to enlarge any of the
numberless miniature vapour holes to obtain pure crystallised
sulphur hot from the bakery, and at the same time to convert these
holes into more active vapour jets. The streams that issued in
various directions were of boiling heat, limpid and tasteless; but,
though sulphur was everywhere strewn around, it did not appear
to be in quantities sufficient for shipment. After an hour's
stop, we returned to our ship greatly delighted with the visit,
and much indebted to our obliging captain for having put it in
our power to enjoy it."

Mr Heaphy has kindly furnished me with a map and views
of this singularly interesting island.

If we take a wider view of the geological features and the
physical outline of these just described high plains and plateaus
consisting of regular layers of trachytic rocks, breccia, and tuff,
we shall find that the steep cones of Ruapahu and Tongariro
rise from the centre of a vast tuff cone of extremely gradual
inclination, the basis of which occupies the whole country from
shore to shore - from East to West - having a diameter of 100
sea miles, and forming the largest cone of tuffs, or in other words,
the largest crater of elevation, in the whole world.