Cox.—On the Mineralogy of New Zealand. 407 
Oligoclase, 2 A} Si ° + (Na, Ca)? Si?, is mentioned by Dr. v. Haast iu 
quartz porphyries of Mt. Misery and Malvern Hills (Jurors’ Rep. N.Z. Ex., 
1865, p. 257), and R. Daintree, Esq., F.G.S. (Trans. N.Z. Inst., vol. vii., 
p. 458), mentions the occurrence of a plagioclase felspar, which is probably 
oligoclase, in granite from Snowy Peak Range. 
Obsidian is mentioned, by Dr. v. Hochstetter, with rhyolites in the 
Taupo district (New Zealand, Eng. ed., p. 407); by Dr. v. Haast, on the 
sides of trachytie dykes (selbands) in Banks Peninsula (Jurors’ Rep. N.Z. 
Ex., 1865, p. 257, and Trans. N.Z. Inst., vol. xi., p. 504); and by Mr. 
J. A. Pond, in the voleanie rock from Mr. Firth's well near Mt. Eden, 
Auckland (Trans. N.Z. Inst., vol. vii., p. 406). Its distribution in the 
North Island is widespead in the voleanic regions which occupy the central 
and north-east portions of the island; but, so far as I am aware, no solid 
flóes have been discovered, and the mineral has only been found in isolated 
blocks. It was formerly largely employed by the Maoris for the manufac- 
ture of weapons and implements. There are several specimens in the 
collection of the Colonial Museum from Taupo and White Island. 
Pumice.—Is found throughout the voleanic region of the central portion 
of the North Island whence it is brought down to the sea by rivers, and 
distributed along the coast by the action of the tides and currents. It is 
mentioned by Dr. v. Hochstetter (New Zealand, Eng. ed., p. 43) as 
occurring in plateaux round Lake Taupo, 2,000 feet above the sea and 
he states (p. 884) that Mr. Grace's house is built of it. It is mentioned 
(Jurors’ Rep. N.Z. Ex., 1865, pp. 85, 253) from the beach near Napier, 
where it is found in considerable quantities, brought down by the rivers 
from the north and also from Waikato, and Mr. J. C. Crawford (Trans. 
N.Z. Inst, vol. vi, p. 856) states that it occurs in large quantities at 
Tokano and (Trans. N.Z. Inst., vol. viii., p. 877) that pumice floats down 
the Wanganui River in such quantities that it would be easy for a ship, 
anchored in the river, to put out nets and so load the ship. Around the 
voleanie group of Ruapehu and Tongariro there are immense areas covered 
with pumice, and at Kereru, Napier, and many other localities on the east 
eoast of the North Island, there are extensive deposits of compact white 
pumice-sand, which are mentioned by Mr. McKay (Geol. Rep., 1876-77, 
p. 81). 
Pitchstone.— The only district in New Zealand where this mineral occurs 
is between Mt. Somers and Snowy Peak, where it is associated with quartz 
porphyries of which it appears to be the vitreous form, a complete series repre- 
senting the change from a fluid pitchstone, through various stages, to a 
quartz porphyry with felsitic base and small crystals of quartz and garnet 
in which no fluxion structure is visible. It is of all colours, from grey to 
