82 
I'llli GEOLOGY OF KELSON - . 
V 
during the summer from the south, is a local wind of Blind 
Bay, due to the same physical configuration of the country. 
The calm heated air of the Waimea plains and of the low hills, 
rising in obedience to physical laws into the higher levels of 
the atmosphere, is suddenly replaced by volumes of colder and 
denser air, which rush down towards the plains from the 
mountain ranges behind. 
I have made these remarks in order to offer an explanation 
of some of the most striking peculiarities of the Nelson climate 
—the Montpellier of New Zealand. 
i 
II.—GEOLOGICAL FEATUBES. 
The western and the eastern ranges of Nelson are totally 
different in their geological character. The western ranges 
consist of primitive formation, being built up of old crystalline 
schists, or metamorphic rocks. The eastern ranges are the 
oldest sedimentary strata, primary formation, broken through 
in places by masses of plutonic rocks. The lower undulating 
hills lying in the angle between the two ranges are nothing 
but an immense accumulation of debris from the mountain 
ranges on either side, rolled together by the action of the 
sea, which in former ages washed the bases of the mountains. 
When I say Gold in the western ranges, Copper in the 
eastern ranges, and Coal in the basins between them, I have 
indicated the chief mineral characteristics of the region 
referred to. I will now speak more in detail of the 
(1) Primitive Formation of Che Western Ranges. 
Taking a cross section from east to west, through the 
western ranges, we find the sub-divisions of the primitive forma¬ 
tion succeeding to one another in their normal geological order. 
(al) Gneiss and Granite Zone. —The western shores of 
Blind Bay, from Separation Point to Riwaka, consist of 
granite, bordered on the eastern side opposite to the Tata 
Islands bv gneiss. This same zone of granite and gneiss may 
be traced in a southerly direction up the Motueka River to the 
confluence of the Wangapeka, and is cut through by the 
Buller River, where it enters the gorge of the Devil’s Grip on 
the western ranges, and extends all along the eastern slope of 
the mountains as far as the Rotorua Lake. 
/ 
