448 JOURNAL OF SCIENCE. 
recorded. ‘The only active voleano in New Zealand is Tongariro, and 
its eruptions are feeble. White Island, in the Bay of Plenty, appears 
to be in the solfatara stage ; it has never been known in eruption, and 
there is no appearance in it of any recent lava streams. Two interesting 
sections of voleanoes occur in the sea-cliffs of the North Island, the one 
on the west coast between Port Waikato and Raglan, the other situated 
at the west head of the Tamaki River, near Auckland. I have it on 
the authority of the late Mr. Heaphy, that this latter is the same as 
the one figured by him (in the Quart. Journ. Geol. Sc. XVL., p. 242), 
and copied into the works of Scrope and Judd. This is the only crater 
near Auckland that is cut through by a sea-cliff, and I quite agree with 
Dr. Hochstetter that it is a tuff crater only, without any lava stream. 
A very interesting generalization can be made of the distribution 
of the volcanic rocks in the North Island. I have already pointed out 
that judging from the relative positions of the Maitai and Hokanui 
systems fit is probable that the geanticlinal of the South Island passes 
through the centre of the North Island from Wanganui to the Bay of 
Plenty. Now on the north-west side of this axis the trachytes of early 
tertiary date were followed by dolerites and basalts. Wesee this in Mt. 
Egmont, Mt. Karioi near Raglan, in the Lower Waikato, and Mercury 
Bay forming a line parallel to the geanticlinal, to the east of which 
there are no basic rocks, while to the west, basic rocks occur, but no . 
rhyolites. On the geanticlinal itself from Ruapehu to the Pay of 
Plenty, the trachytes (or andesites) were followed by rhyolites without 
the admixture of any basic rocks. To the east of the axis, basic rocks 
occur again on the east coast of Wellington, but these are stated to be 
older. I have mentioned that a line of granitic exposures occurs along 
the geanticlinal of the South Island from Paringa to Separation Point 
in Nelson, and the question naturally suggests itself are these rhyolites 
of the North Island derived from a northerly extension of the granitic 
zone of the South Island? It seems possible that the acidic rocks may 
be nearer the surface here than they are in the northern parts of the 
Province of Auckland, and this may account for the eruption of 
rhyolites only in the centre of the North Island. They may be merely 
a réchauffé of the Maitai granites of the northern part of the 
geanticlinal. . | 
Hot Springs.—-In the South Island hot ‘springs are known only in 
two localities, one in the Hanmer Plains, Amuri County, the other near 
Lake Sumner, about forty miles south-west of the first. In the N orth 
Island there is only one hot spring east of the main range. It is near 
Waiapu, in the East Cape district. Bnt west of the main range they 
are very numerous. All the more important ones lie in a broad band 
along the axis of the geanticlinal, from the base of Tongariro through 
Lake Taupo and the Upper Waikato to Lakes Rotomahana and — 
Rotorua, forming one of the most wonderful regions in the world. 
North of this region the hot springs are isolated. They occur at 
Pupunui, on the Thames, near Lake Whangape, in the Lower Waikato, 
at Waiwera, a few miles north of Auckland, at Mahurangi ; also near 
the Bay of Islands, and on the Great Barrier Island. Geysers, fuma- 
roles, mud-volcanoes, and springs depositing siliceous sinter are confined 
to the central rhyolitic region of the North Island. 
Minerals—An exhaustive list by Mr. S. H. Cox, of all the 
minerals at present known from New Zealand, will be found in Vols. 
