C.— 13. 
10 
On the east side of the Kokatahi Plain granite again forms the outer western slopes of the 
higher mountains, and this is followed by the same sequence of rocks that have been mentioned in 
describing the middle and upper parts of the Arahura Valley. 
On the south-west side of the Hokitika Valley, below the Gorge, lies Constitution Hill, 
which is in part composed of slate. Between this and the hilly country, along the road-line from 
Rimu to Ross, lies the Big Swamp, from •which iu times of flood a portion of the surplus waters of 
the Hokitika finds its way into Lake Mahiuapua. 
The hilly country between Rimu and Ross is densely covered with forest growth, and the 
details of the surface are for the most part unknown, or known only to a few explorers. Its general 
character is, however, quite evident from what can be seen along the Ordinary route of travel, and it is 
warrantable to say that the whole is overspread with morainic heaps, that towards the Totara River 
only have been modified by the action of running water. Old river-gravels underly these morainic 
heaps, as seen at Back Greek and Seddon’s Terrace, and towards the margins they may have been 
acted on by streams from, or the whole body of the Hokitika, as in the case of the Rimu Plat. 
Totara Watershed — Boss and Mount Greenland . — The Totara River takes its rise from Mount 
Fraser and the Cedar Creek Saddle, leading into the Mikonui Watershed. The upper and middle 
parts of its course are along a mountain-valley between Mount Greenland and Constitution Hill, 
and the river is so confined till reaching and passing the outer spurs of Mount Greenland. Seaward 
of this the Totara receives Donnelly’s Creek, and flows along the north side of Ross Flat to the 
Totara Lagoon. 
Between the hills and the sea from the Mikonui to the Totara extends a tract of low, level 
country, having its greatest breadth to the north. From the lower slopes of the spurs of Mount 
Greenland gold has been traced into this flat, and the portion known as Ross Flat has in past 
time yielded a great amount of gold, and it is known that considerable areas of very rich ground 
await working, capital and machinery being required to do this. 
East of the alluvial plain the ridge of front hills are composed of Pliocene gravels (“ Old- 
man bottom”), and behind or on top of these, in Mont d'Or, there is a development of what 
appears to be a glacier deposit. Mount Greenland, like the bulk of Constitution Hill, is formed of 
sandstone and slates belonging to the Maitai series of the New’ Zealand Geological Survey classi- 
fication, and thus corresponds in age with the auriferous rocks of Reefton. The Cedar Creek rocks 
are of the same age. Quartz reefs occur on both the east and west slopes of Mount Greenland, 
but, though '■a considerable amount of prospecting has been done on the Cedar Creek line, the 
prospects have not been such as were anticipated, and “reefing,” as a form of gold-mining, is deve- 
loping but slowly in this part of the district. 
DETAILED DESCRIPTION. 
Table of Formations. 
Sedimentary. 
I. Recent. 
Glacier, river alluvia, littoral. 
Ia. Pleistocene. 
High-level old river-channels and terraces. 
II. Pleistocene and Younger Pliocene. 
Extended glacier deposits outside the limits of the mountains. River-deposits 
formed prior to the advance of the glaciers. Marine gravels, &c., containing 
black-sand leads. 
III. Older Pliocene and Upper Miocene. 
Humphrey’s Gully Beds, “ Old-man bottom,” Brown sands. 
IY. Lower Miocene (Marine Tertiary-beds). 
Blue fossiliferous sands and marly clays. 
VI. Cretaceo-tertiary and Cretaceous. 
Upper, Middle, and Lower series. 
X. Triassic (?). 
Beds in the Upper Teremakau Valley, resembling the jasperoid and diabasic beds 
of the Selwyn Gorge, Canterbury. 
XII. Carboniferous. 
Maitai series — Westland formation of Haast. 
XIII. Devonian. 
(a.) Reefton series. 
(h.) Slightly altered sub-metamorphic rocks. 
Metamorphic. 
Mica Schists. 
Upper, middle, and lower mica-schists. 
Gneissic schists. 
Crystalline schists and metamorphic granite. 
Plutonic. 
Massive and intrusive granites, &c. 
