148 
The N.Z. Journal of Science and Technology. [Sept. 
THE GEOLOGICAL FEATURES OF THE BROKEN 
RIVER COAL AREA. 
(Continued, from page 104.) 
By R. Speight, M.A., M.Sc., F.G.S., F.N.Z.Inst., Curator of the 
Canterbury Museum. 
C. STR ATIGRAPH Y —c ontinued. 
Waipara Series— continued. 
* 
(b.) Structure of the Coal-measures. 
(See Fig. 7.) 
An examination of the area shows that the coal-measures have on the 
northern side of the river a general north-west and south-east strike, and 
a dip to the south-west. In Iron Creek these beds are bent up into an 
acute syncline, and the connecting portions accommodate themselves to 
these deformations without any marked dislocation. The structural 
phenomena are thus analogous to those of the Trelissick Basin (Speight, 
1917), and result in all probability from the formation of a tectonic basin, 
largely due to faulting or folding of an area of peneplain with its covering 
veneer of Tertiary sediments towards the close of the Tertiary era. It 
is probable that this settling was not uniform over the area of depression, 
but more marked in subordinate areas forming basins such as Castle Hill, 
or with strips passing into basins as in the case of Sloven’s Creek (to be 
referred to later), so that ridges of greywacke left standing as horsts, or not 
so much depressed, persisted after the general settlement. The resultant 
repacking of the blocks has caused a more acute folding and faulting where 
the edges of the weaker overlying sediments have been brought against 
the hard resistant rocks forming the edges of the basin or the ridges within 
its periphery. This will account for the disturbance of the beds, with its 
attendant folding and acute crushing, which has occurred along the line 
of Alum Creek and in Iron Creek. 
(c.) Quality and Quantity of the Coal. 
The following analyses made by Mr. W. 0. R. Gilling, Research Scholar, 
under the direction of Dr. W. P. Evans, at the Canterbury College Labora¬ 
tory, show that it is a coal of very good quality :— 
No. 1. 
No. 2. 
No. 3. 
Water 
.. 15-98 
15-95 
16-32 
Ash . . 
.. 5-40 
5-22 
6-71 
Fixed carbon . . 
.. 33-53 
33-13 
33-68 
Volatile hydrocarbons .. 
.. 45-09 
45-80 
43-29 
100-00 
100-00 
100-00 
All these samples are from Alum Creek, and were collected by myself. 
No. 1 was from the lowest seam exposed in the creek ; No. 2 was from a 
seam exposed on the east side of Alum Creek, probably lower in the series 
than No. 1 ; No. 3 was from the large seam exposed in the slip, higher in 
