1920 .] 
Speight.—Broken Biver Coal Area. 
149 
the series than No. 1 and lying to the south-west of it. All samples were 
taken from workings and not from outcrops. 
Mr. Grilling informs me that the quantity of sulphur, which in the 
analyses is included in the volatile matter, is uncommonly high—up to 
7 per cent.—and that it is not in combination with iron as pyrites but as 
an organic sulphide. * The uniformity of the analyses is remarkable, and 
they also agree in this respect with the analysis published in the Annual 
Report of the Colonial Museum and Laboratory, 1889, p. 47. Though it is 
uncertain what seam this sample was from, yet it is reasonably certain 
that it came from one of the seams indicated above. The other analyses 
of coal, mentioned in the next year’s report of the Colonial Laboratory 
(1890, p. 22), are evidently from similar coals, although their fixed carbon 
is high and volatile matter less. 
It is reasonable to infer that the high quality of the coal in Alum Creek 
is due partly to changes produced in the coal as a result of pressure, since 
in other parts of the area remote from that where the folding is somewhat 
pronounced the coal appears to be an ordinary brown coal. It is unfor¬ 
tunate that this pressure has had the effect of crashing the coal, so that 
at times it falls to pieces very readily when exposed to the air ; on the 
other hand, in some places where the pressure has been on a moderate scale 
Fig. 7. —Section from Alum Creek across Iron Creek. Direction, east and west. 
Distance, miles. 1, Greywacke; 2, sands, sandy clays, fireclays with 
coal; 3, sandstone ; 4, white sands ; 5, green sands. 
it stands the weather almost as well as a bituminous coal. Outcrops, even 
when exposed to alternate wetting and drying, have to my knowledge 
shown little, if any, surface change for over twenty years. 
On the extreme western side of the area, where sills have been intruded, 
the original coal has been of somewhat poor quality, so that the value of 
the coked material is not very great, and, further, the extent is probably 
quite small. 
The amount of coal available in the field is entirely problematical, and 
mining operations have not aided materially in framing an estimate, since 
little prospecting has been carried out in advance of the development. As 
far as can be inferred from the data at present available, the seams take 
the form of lenses or wedges, and make and thin out when traced along 
both strike and dip. It is possible that adjacent seams may compensate 
for this variability by changes proceeding in the reverse direction—that 
is, an adjacent seam may thicken as an upper or lower one thins—but 
nothing definite can be said at present. However, the general evidence 
points to a diminution in the total quantity of the coal in the measures 
as they are traced toward Winding Creek and up Iron Creek. 
This irregularity of the seams is, in my opinion, due to the conditions 
under which they were deposited. The pronounced current-bedding of the 
associated sands and sandstones, and the extreme variability of the direction 
