174 The N.Z. Journal of Science and Technology. [Sept. 
rock in which the only crystals distinguishable by the eye are a few small 
feldspars. 
Coal-outcrops. 
In the valley of Alum Creek, a small tributary of Broken River travers¬ 
ing the eastern part of the coal-measure area south of the river, several 
seams of coal outcrop, one at least of considerable thickness and good quality, 
but they stand almost on edge, and are so contorted as to have little value 
from a mining point of view. To the westward the beds flatten, but a few 
chains from Alum Creek are interrupted by a fault with a considerable 
downthrow to the westward. From this point to near Winding Stream the 
coal-measures are fairly regular, and show a moderate dip to the west of 
south. On the north side of Broken River a sandstone cliff shows several 
seams, the lowest of which at a point 1,430 ft. above sea-level (barometric 
height) is being opened up by three adits, none of which was of any great 
length at the time of my visit. These show the seam to have a maximum 
thickness of 9 ft. of clean coal, but not far from the entrance of each adit 
stone bands appear, and a roll has the effect of further diminishing the 
thickness of the coal-seam. The main drift is projected on a north-west 
course, with an up-grade of 1 in 12, which will bring it out in the valley of 
Winding Stream, quite a mile away.* The coal being mined is hard, bright, 
and evidently very suitable for household use. It is a high-class brown 
coal, with about 15 per cent, of contained water. 
Higher up Broken River the coal-horizon, owing to the dip of the strata, 
is below the level of the stream, and a considerable area to the south of the 
river which probably contains workable coal will have to be developed by 
means of a dip drift. Above Iron Creek, however, thick coal is seen on the 
south side of the river, and, as already mentioned, is intruded by a dyke of 
some size. This appears as a sill-like band in the coal at two points. At 
one of these the coal for 2 ft. above the igneous rock is converted into a 
hard, black stone-like material, which may be termed coke rather than 
anthracite. Above this for 2 ft. or 3 ft. the coal is in the form of small 
prisms of coke, exactly resembling columnar basalt in structure, except that 
the columns are only from ^ in. to 2 in. in diameter. Above the prisms 
the coal is apparently unaltered. A little farther up stream several feet of 
prismatic coke directly overlies the dyke. Below the igneous rock and 
' k frozen ” to it is 3 in. of stony coke, passing downward into apparently 
unaltered coal. It is possible that the “ coke ” is partly graphitized. 
Of considerable interest is a hitherto undescribed area of coal-measures 
occupying the low ground between No Man’s Land and Mount St. Bernard 
to the north. Coal outcrops at a point known as Coal Creek, between the 
small lake named Vagabond’s Inn and the railway-line (barometric height 
1,850 ft.). It is not very thick, but is associated with a considerable thick¬ 
ness of carbonaceous shale. The strike is 211° magnetic, and the dip 70° 
to the north of west. To the north-west the sandstones overlying the coal 
are seen to show gentle dips, so that the steep dip observed at the coal-out¬ 
crop does not persist in that direction. Over a mile to the southward coal- 
outcrops belonging to more than one seam are again seen a short distance 
* Since this was written coal-winning on the north side of Broken River has been 
discontinued, but a dip prospecting-drift is in progress. At present (March, 1920) the 
Mount Torlesse Collieries is working the steeply dipping coal-seams on the south side of 
the river. These yield very friable coal. 
