Livrnsimpog.—On some of the N. Z. Minerals in the Otago Museum. 499 
The mica was not perfectly pure; it was found difficult to separate it 
completely from the other constituents of the rock; the diffieulty was 
mainly due to the smallness of the quantity at my Boa, 
Alkalies in Felspar (Albite). 
Potash =p v» Ta eve 1071 
Soda WE *» - $* .. 5'590 
6-661 per cent. (Liversidge). 
Garnet.—Breaksea Sound. _ 
An embedded erystal (the rhombic dodecahedron) broken across. The 
matrix is syenite, having the wavy foliated structure of gneiss. Imme- 
diately around the garnet the hornblende is almost entirely absent, which 
causes that part of the matrix to be much lighter in colour, and conse- 
quently the garnet is shown up to much greater advantage. 
It is highly probable that the hornblende and garnet are not very 
dissimilar in chemical composition, and that when the rock underwent 
metamorphism, and its constituents were free to re-arrange themselves, 
the garnet ** nucleus," or centre of crystallization, had the power to abstract 
and build up certain of the rock constituents which would have other- 
wise assumed the form of hornblende. Hence the probable reason of 
the absence of hornblende in the immediate neighbourhood of the garnet. 
It would be very interesting to put this suggestion to the proof by chemical 
analysis, should additional specimens be obtainable. 
Limestone.* Crooked Arm, West Coast.—(Labelled ** Cipillino.") 
A white saccharoid limestone or marble, containing small erystals of 
brown mica, a little quartz, and a few scales of graphite. 
The variety of marble known as cipillino contains tale or chlorite, hence 
it is marked by green-coloured streaks and veins. 
This specimen cannot therefore be classified with it. 
Analysis. 
Carbonie acid i re = s. 88-284 
Tron sesquioxide ana siio =< i s P988 
Lim “s 3 Š 48:269 
Magnesia m vi ue e ši 402 
Mica, silica, ete, insoluble in acid .. es s» 9-459 
Undetermined constituents ee vi ¿s 7333 
100-000 (Liversidge). 
Halloysite.1—Water of Leith, Dunedin. . 
Àn opaque white earthy substance, soft and soapy ; associated with it is 
a little black halloysite ; when immersed in water it gives off air bubbles 
* Report West Coast Expedition, Otago Gazette, 1863, 459. 
Rep. N.Z. Exh., 1865, 438. 
