488 
% 
The formations are following from West to East pretty much 
in the natural sequence of their geological age; sections taken in 
this direction will , therefore , explain the geological structure most 
satisfactorily. 
The western slope and part of the central chain consists of 
crystalline rocks and metamorphic schists, highly auriferous and 
resting upon a basis of granite , that presents itself here and there 
to the view in the rugged bluff's and declivities on the West coast . 1 
bury 1864. — Dr. J. Haast, Report on the Geological Exploration of the West Coast 
Canterbury 1865. — Dr. J. Hector, On the Geology of Otago (Quart. Journ. of the 
Geol. Society, London 1865. 
1 This granitic and metamorphic zone of the Southern Alps, so highly impor- 
tant from the auriferous character of the rocks (See Chapter V.) is, as Dr. Haast 
describes it, composed of varieties of granite, syenite, pegmatite, gneiss, mica-, 
hornblende -chloritic and talcose schists, dioritic porphyries, trap rocks and a great 
variety of clayslates and quartzites. Dr. Hector explains the general geological 
features of the Otago Province as follows: u The southwestern part of the Province 
is composed of crystalline rocks, forming lofty and rugged mountains, intersected 
by deeply cut valleys, which are occupied on the west by arms of sea, but on the 
east by the great lakes. The base -rock of this system is a foliated and contorted 
gneiss. Associated with it are granites, syenites and diorites. Wrapping round this 
batch of crystalline strata and sometimes resting at great altitudes (say 5000 feet) on 
its surface are a series of hornblende-slates, soft micaceous and amphibolic gneiss, 
clay-slates and quartzites, associated with felstone- dykes, serpentine, and granular 
limestone. 
To the eastward of these two formations the country is traversed by a depres- 
sion that widens towards the south, and enters the mountain-chain by a pass only 
2000 feet in altitude above the sea; this is the Greenstone Pass. Along the line of 
this depression and resting on the last mentioned slates etc. (unconformably?) are 
well bedded sandstones, shales and porphyritic conglomerates, together with soft 
greenstone-slates and diabase-rock in patches. — To the eastward of the depression 
we have a great development of the auriferous schistose formations, shaped as a 
flattened boss, and rising to 4000 feet. The strike of the auriferous schists is on the 
whole N, N. W. 1 have divided the schists into three parts. 
1. Upper. A grey arenaceous, almost slaty rock containing but little quartz in 
the form of veins and laminae* 
2. Middle. Soft blue slates, often highly micaceous and intersected with quartz- 
veins of small size. The thickness of this formation is not more than from 
100 to 200 feet and is probably the same from which most of the gold in 
Western or Lake-goldfields has been derived by the direct erosion of glaciers 
and mountain torrents. 
3. Lower. Contorted schist. This is a clay-schist, foliated, not with mica, nor 
with felspar, but with quartz. It is often chloritic and in the upper part the 
quartz is nearly wanting. Gold occurs segregated in the interspaces of this 
