18 
The N.Z. Journal of Science and Technology. 
[Mar. 
Reefton Coalfield.* 
By J. Henderson, D.Sc., Mining Geologist, N.Z, Geological Survey. 
The outcrop portion of the Beef ton Coalfield consists of a strip of 
coal-measures extending from south of Beefton to north of Capleston, and 
resting on the flanks of the hills that form the eastern side of the great struc¬ 
tural depression between the Paparoa and Victoria Banges. The measures 
dip westward at angles that vary between 1 in 2 and 1 in 8, and disappear 
beneath the gravels of the floor of the valley. The streams draining from 
the eastern uplands have cut their valleys through the coal-measures, and 
the coalfield as exposed consists of a series of small blocks of coal- 
measures separated by gravel-filled valleys of greater or less width. At 
one time the coal-measures formed part of an ancient land surface that 
was later smothered by thick deposits of stream-gravels. These, though 
now in great part removed, still form the tops of the interfluvial ridges 
and terraces. Thus the outcrops of the seams are confined for the most 
part to the lower slopes of the valleys, and the area occupied by any seam 
in a spur is largely a matter of inference and not of measurement. 
The most northerly known coal-outcrop belonging to this coalfield is 
near the junction of Italian Gully and Baglan Creek, where coal mixed 
with clay and sandstone occurs in a crush-zone. Involved in the same 
fault, thick outcrops of crushed coal appear in Howell’s sluicing claim 
and in Burk Creek (of which Baglan Creek is a branch). In Coal Creek, 
another branch of Burk Creek, a 21 ft. seam is reported, and in a small 
eastern branch of Coal Creek a large outcrop is exposed. Near the saddle 
between Coal and Little Boatman Creeks Mr. F. W. Archer has worked 
two seams for many years. Becently he has driven a tunnel from Little 
Boatman Creek at a point about 250 ft. above the Township of Capleston. 
In this locality at least four workable seams are known. The lowest, 20 ft. 
thick or more, rests on micaceous claystones, and is 12 ft. above a thin 
coal-seam 1 ft. to 2 ft. thick, which in turn is separated from the basal 
grevwackes by about 100 ft. of coarse grit and fine quartz-conglomerate. 
The roof of the large seam consists of about 1 ft. of carbonaceous shale 
succeeded by 30 ft. of fine sandstone. Next follows a 5 ft. seam of 
coal contained in thin layers of carbonaceous shale; then 50ft. of grit 
and sandstone ; a coal-seam 12 ft. to 16 ft. thick ; 50 ft. of grit, sandstone, 
and shale ; and a coal-seam 10 ft. to 12 ft. thick, overlain by massive layers 
of grit and fine conglomerate. The coal-outcrops to the north of this 
locality already mentioned must belong to one or more of these four seams, 
but enough work has not'-been done to allow of any safe correlations. 
A powerful fault, striking north-west, separates ther ancient rocks from 
the coal-measures along the north-eastern side of the Burk Creek valley, 
and has caused the steep dips and shattered condition of the coal-seams 
of that locality. Immediately above Capleston, half a mile to the west 
of the point where Mr. Archer has recently opened the large bottom seam, 
the same seam has been worked by Coghlan Bros, for many years. This 
is the only one of the four workable seams known to occur in the basin of 
Little Boatman Creek that has been traced to the westward as far as 
* Tliis account includes no description of the numerous patches of coal-bearing 
strata occurring on the hills east and south-east of Reefton. 
