1919.] 
Departmental Eeports. 
397 
floor are favourable for cheap working. The seam lies nearly flat, and no 
fault or other unfavourable structure was observed in the strata over a wide 
area round the outcrop. Access to the seam is not difficult. Any vessel 
able to cross the Mokau bar can at high tide reach the mouth of the Manga- 
awakino, thirteen miles from the sea. The valleys of the Mangaawakino 
and Kaipaku are wide and open for three miles, and are traversed by an old 
sawmill tram-line of easy grade. The rise in the three miles is about 90 ft. 
The outcrop described is less than half a mile from the end of the valley- 
flats. 
A studv of the sections of the coal-measures of the Mokau district makes 
c/ 
it clear that the coal-seams may vary in thickness within short distances. 
Hence it is essential that no assumptions be made as to the extent of the 
workable thickness of any seam. This knowledge can be obtained only by 
prospecting. The thick seam outcropping in the bed of the Kaipaku can be 
easily traced down the valley by surface trenching. It may be noted that in 
this direction thick coal is reported to have been uncovered in the bed of the 
Mangaawakino a little below its junction with the Kaipaku. At this locality 
much silt occurs in the stream-bed, and no coal was found. Eastward of 
the main outcrop in the Kaipaku the coal horizon is below the stream- 
channel, and the extension of the seam in that direction can be determined 
only by boring. East-south-eastward, 30 chains from the Kaipaku outcrop, 
is the 6 ft. seam in the Mangaawakino. Northward of the Kaipaku—- 
that is, to the “ rise ”—the streams have not cut to the coal horizon, and a 
large area of level free coal may exist in this direction. Boring will be 
necessary in the valley of the Mangaawakino to ascertain the thickness of 
the coal to the “ dip.” If the gentle inclination of the strata observed in 
outcrops be maintained the coal horizon deepens only at the rate of 350 ft. 
per mile. 
Ohura River Section. 
The western rim of the basin of the Ohura River, drained by the 
Mangaroa and its branch the Waitewhena, is formed of coal-measures and 
■the strata overlying. Coal crops out at many points for a distance of 
fourteen miles along the plateau-edge, which is the outcrop portion of 
what may be termed the Ohura section of the Taranaki Coalfield. The 
strata have a general westerly dip at low angles, and although a few small 
faults were observed the rocks as a whole are but little disturbed. To 
the eastward the coal-measures have probably been down-faulted, but 
positive evidence of the presence of the powerful fracture necessary on 
this supposition is scanty. 
Mr. M. Ongley, on pages 8 and 9 of the 11th Annual Report of the N.Z. 
Geological Survey, has a report entitled “ Coal of Waitewhena District, North 
Taranaki.” This is accompanied by a map which shows numerous coal 
outcrops over a distance of seven miles at the northern end of the Ohura 
section of the coalfield. He states there are thirty outcrops where the 
coal is 10 ft. or more in thickness. Many other outcrops occur where the 
full thickness of the coal could not be measured. 
In the southern portion of the Ohura section coal is exposed at many 
points. Near the end of the road along the Mangakara Valley, where the 
stream breaks into two equal branches, the coal-seams outcrop at points 
650 ft. and 690 ft. above sea-level. The lower seam is covered bv debris, 
but the upper was examined at two points, where it was respectively 3 ft. 
and 4 ft. thick. About two miles south of this locality, 25 chains past the 
end of the road along the Huhatahi Valley, two seams are exposed in the 
stream-bed, the lower 18 in. thick and the upper 3J ft. The latter seam, 
however, contains many dirt bands, especially in its upper portion. The 
