378 
PROCEEDINGS OE SECTION C. 
exploration has not gone much beyond that limit, -except in the 
instance just mentioned. Granite comes in about half-way down the 
face of the hill, northward, in the direction of the township of 
Watsonville, which is situated at the foot of the range. Some of the 
mines are opened in the porphyry within a short distance o£ the 
granite, but I am not aware of any working in the granite itself. 
At Irvinebank, 10 miles west from Watsonville, there is more 
lode-mining. The tin lodes occur here in sedimentai’y rock, which is 
understood to correspond with the greywackes and shales of the 
Montalbion silver country, 4 miles further on. # The composition of 
the lodes is mainly chlorite, arsenical and iron pyrites, and spatliose 
iron being accessories 
The Great Southern and Vulcan Mines in this neighbourhood 
have produced considerable quantities of ore, as have also several 
other mines of less importance. In the two referred to, the ore 
deposits have taken the form of large shoots. The Great Southern 
shoot extended almost vertically from the surface of the ground dow r n 
to 150 feet, in a massive state, covering a horizontal sectional area of 
from 600 to 1,000 feet. At that depth it diminished in bulk and 
dipped at a low angle toward the west. 
The Vulcan Mine has been productive from the outcrop of the 
lode down to 300 feet, the ore-shoot sometimes extending over an area 
as large as that of the Great Southern. A fresh body of ore has 
recently been struck here in. the deepest ground. In this mine 
bismuth in small quantities is associated with the tin. The Great 
Southern Mine has yielded 1,321 tons, and the Vulcan over 1,900 tons 
of dressed tin. 
Glenlinedale, about 10 miles to the south of Irvinebank, furnishes 
an instance where a large outcrop of tin-bearing Btone was found at 
the junction of the lode with a strong el van dyke. The country rock 
is schistose, sandstone, and shale. Granite becomes exposed about 
£ mile from the mine, towards the south. The principal constituent 
of the lode is a hard, dark-coloured, brittle quartz. The heavy surface 
outcrop, which covered a sectional area of 1,000 feet, was followed 
down to about 1 50 feet in depth, when it broke up in a mass of vertical 
layers of sandstone. The yield of ore from the stone taken from this 
mine 'was 6 per cent. 
At California Creek, 28 miles beyond Irvinebank, to the south- 
west, cassiterite presents itself in lodes in the granite ; but the ground 
is hard and the veins narrow. In the same neighbourhood tin occurs 
in lodes in a bed of sedimentary rock lying between granite hills. 
Where the lodes crop out in the granite the ore is associated with 
quartz. In the stratified rock it occurs chiefly with chlorite, as at 
Irvinebank. 
At Coolgarra, lodes have been wrought in the greywacke and 
shale, but granite appears over a large portion of the outlying country. 
At Koorboora the lodes occur in stratified rock, and at Imreka 
Creek in both stratified rock and granite. 
* This formation, from Mr. Jack’s recent investigations, presents indications of 
a Devonian character. 
