Buatrr.—On the Building Materials of Otago. 145 
form of large boulders, or erratic blocks, like the Sarsen or Druid stones of 
the South of England. Numbers of them exist on the ranges about Kai- 
korai, Tokomairiro, and Kaitangata. They yield stone of a red or brown- 
ish colour that varies in texture from coarse sandstone to conglomerate with 
large pebbles. The blocks are usually harder than ordinary sandstone ; 
but are sometimes wanting in cementing material, so much so that the 
stone easily reverts, under pressure, to its original gravel. 
The grits furnish good building material for massive coarse work ; but 
are comparatively valueless for architectural purposes. The railway bridges 
at Chain Hills and Glenore are built of this kind of stone—that in the former 
work is comparatively fine in the grain, but the others are coarse and full 
of pebbles. They are both used in large blocks, which, along with the 
dark colour of the stone, tends to give the structures a massive appearance 
very appropriate to this clase of work. 
Closely allied to the grits, and existing under much the same circum- 
stances in the same localities, we have numerous freshwater sandstones. 
They are of various colours; but are all extremely hard and compact, ap- 
parently highly charged with silica. A very handsome stone of this kind, 
found in the Hillend district, has been used in the abutments of the Clutha 
Railway Bridge; it is of a silver-grey colour, and an even hard texture. 
Other samples found in the same locality, and at Chain Hills, are of a 
reddish-white colour, equally compact. Both varieties are too hard for 
dressing with the chisel. There is a good specimen of white sandstone in 
the Museum, from Murison’s Gully, on the Rough Ridge ; in all probability 
it belongs to this class. A connecting link between the grit and sandstone 
proper is found on the western side of the Waihola Lake, from Mary Hill to 
the Gorge. It has a tough granular texture, capable of being easily dressed 
with the pick or chisel, but too hard for smooth work ; its colour is a light 
warm brown, very suitable for architectural purposes. The stone is sup- 
posed to exist in large quantities; but has hitherto been little used, Mr. 
Duff's house is the only building of it that I know. 
The sandstones proper, which embrace all sedimentary rocks in situ, 
are found in immense quantities throughout the Province. Unfortunately 
the more accessible supplies are of an inferior quality, consequently this 
stone has hitherto been little used for building purposes. 
One of the hardest sandstones in Otago is that at the Falls, Gore Town- 
ship, and at other places on the Mataura River, it is of a dark green or blueish 
tint, almost as hard as bluestone and equally unworkable. It is found in 
large blocks, with natural joints and beds, and so is very suitable for massive 
coarse work ; the two bridges over the Mataura are built of this material. 
A sandstone, of much the same quality though scarcely so hard, is 
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