182 Transactions.—Miscellaneous. 
Syenite, as you are aware, differs from true granite only in so far as it 
contains hornblende instead of mica. As mica and felspar are considered 
the perishable ingredients in these rocks, the durability of syenite can 
never be questioned; it is also on the whole tougher and more compact 
than ordinary granite. This stone is found in various localities on the 
West Coast and in Stewart Island, but the chief supply now available for 
industrial purposes is at the Bluff. Practically, the whole of the Bluff Hill 
consists of this material; it could, therefore, scarcely be in a more 
accessible situation. The Bluff syenite is hard and compact, and of a 
uniformly bluish-grey tint of great beauty, consequently it is suitable for 
kerbing, paving, and massive masonry, as well as monumental and archi- 
tectural works. In my opinion, this stone is little, if anything, inferior to 
the famous Aberdeen granite, and I have no doubt the quarrying and 
dressing of it will ere long become an important industry. There is a 
curious variety of syenite found at Milford Sound, the body colour of which 
is a pure opaque white interspersed with oblong rectangular blotches of 
dark grey and black; these blotches are occasionally an inch long by 
three-eights of an cabs in breadth. 
Another vein of syenitic granite exists at Isthmus Sound; the grain is 
rather coarse, but the colour, which is of a uniformly grey tint, is good. 
Pegmatite, or compact granite, is found at Milford Sound and Paterson 
Inlet. The former is of a grey tinge, with large spots of silvery white 
mica of great brilliancy. This is, perhaps, the most beautiful stone in 
Otago; but it is doubtful if its appearance would be permanent out of 
doors. The stone at Paterson Inlet has a pinkish ground, with grey spots, 
and is much coarser in the grain. When the utilitarian appetite of the 
colonist has been satisfied, and he has means and leisure to bestow on the 
ornamental, the beauties of the West Coast granites will be highly appre- 
ciated. 
Although the stones above described vary much in appearance, there is 
little difference in their composition, and they are all embraced in the 
generic name of granite. All granite rocks are composed of felspar, 
quartz, mica, and hornblende, and the variety is due entirely to the number 
of the ingredients that it contains and the proportions in which they are 
mixed. An undue preponderance of mica and felspar in granite—particu- 
larly when the latter is alkaline—is supposed to render the stone liable to 
loss of colour and to decay ; but, with that exception, granite of all kinds 
is practically imperishable. 
I have compared Mr. Skey’s analysis of the Otago granites with that of 
the Irish varieties given in “‘ Juke’s and Geikie’s Geology,’ and find that, 
