1921.] 
Departmental Report. 
297 
DEPARTMENTAL REPORT. 
Tangarakau Coalfield, North Taranaki. 
By P. G. Morgan, Director, N.Z. Geological Survey. 
In accordance with instructions, I left Wellington for North Taranaki on 
the 4th October last. I reached Tahora next night, and spent the 6th, 
7th, and 8th examining coal-outcrops and other points of interest in the 
Tangarakau Valley. On the 11th I returned to Wellington. 
Access. 
At the present time the Stratford-Okahukura Railway is open for 
ordinary traffic as far as Kohuratahi, forty-three miles from Stratford and 
seventy-three miles from New Plymouth. Rails have been laid for another 
four miles to Tahora, to which a Public Works Department train runs twice 
a week each way. Beyond Tahora the line is being continued down the 
Raekohua Valley, but little progress has yet been made with the construc¬ 
tion. Three miles from Tahora the line will cross the Tangarakau River, and 
thence is to be continued in a general easterly direction through very broken 
country to the Heao Valley, where it will turn northward, ultimately 
reaching Ohura. Originally the railway was intended to tap the Tanga¬ 
rakau Valley about two miles north of Tahora, and thence to follow the 
Tangarakau Gorge for about eight miles, until Paparata Stream was reached ; 
but this route has now been definitely abandoned. From Tahora a road 
runs northward over a somewhat high saddle (the Moki saddle), and thence 
follows the Tangarakau Gorge to Paparata Stream, up which it continues 
to another saddle, whence it drops into the Ohura Valley. No part of 
this road has been macadamized, and in winter-time portions are almost 
impassable. 
Character of Country, Nature of Rocks, etc. 
The district round Tahora contains some ploughable land, but consists 
mainly of a succession of irregular steep-sided ridges, not very high, 
separating a series of narrow valleys. Many of these valleys are somewhat 
U-shaped in cross-section, and the streams they contain run in shallow 
gorges cut in the bottom of the U. Hence during a comparatively recent 
period some cause, such as a slight uplift of the land or the cutting-away 
of a barrier, has enabled the Tangarakau and its tributaries to deepen their 
valleys. The prevailing rock is a fine-grained argillaceous sandstone of 
marine origin. In some places this grades into claystone, in other places 
into a shelly rock not high enough in carbonate-of-lime content to be called 
a limestone. In the Tangarakau Gorge the cliff's are formed of a fine¬ 
grained sandstone, of bluish colour when unaltered, but weathering to a 
light brown. In places, notably in the area surrounding Pukemiro (height, 
1,685 ft.), a band or bands of conglomerate appear. Nearly everywhere 
the strata are almost undisturbed and nearly horizontal. Faults were 
seen in only two places—one in the railway-cutting north of Tahora 
Railway-station, and the other in a cutting on the branch road under 
construction up the Upper Tangarakau Valley. Both these faults seem 
to trend in an east-north-east direction. Dr. Henderson informs me that 
an important fault with north-and-south trend occurs a short distance 
