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The X.Z. Journal of Science and Technology. [April 
to be hardly workable. However, it is apparently commencing to dip 
to the south-west in the farthest workings that I examined—that is, it 
is resuming the general dip of the beds in this locality. It is evident 
that in proximity to the main drive this seam takes the form of an acute 
syncline, of which there is not the slightest trace on the surface where the 
beds are exposed. The synclinal arrangement I attribute, therefore, to 
the conditions of deposit and not to subsequent deformation. There is 
one decided fault to be observed in this part of the area, which has caused 
a movement of the southern part of the beds towards the west, the move¬ 
ment having the nature of a lateral displacement rather than that of an 
ordinary fault. This is no doubt connected with the deformation of the 
beds, which succeeded their deposition, and is quite distinct from the dis¬ 
turbances which were due to mode of deposit. 
On tracing the beds in a southerly direction—that is, towards the upper 
portion of Alum Creek and the saddle between it and Bushy Creek—they 
all appear to thin out, and some of the coal-beds entirely disappear, so 
that the total thickness of the beds in the neighbourhood of the saddle is 
reduced to less than one-third of that which they have in the vicinity of 
the drive. They also become much steeper in dip, so that approaching the 
saddle the dips are between 75° and 90°. The large seam, however, which 
was mentioned as occurring on the eastern slope of Alum Creek continues 
through, and can be traced for nearly half a mile to the south in a western 
branch of Bushy Creek. On the saddle the greywacke is exposed, and the 
coal-measures strike N. 20° W. ; but a little farther along the direction 
is more to the north-west, with a dip of 45° to the south-west. The beds 
consist of sands, sandy clays, and fireclays with thin seams of impure coal. 
There are two seams of workable thickness, the lower one being 5 ft. thick. 
The total thickness of the coal-bearing beds is about 60 ft., and they are 
overlain by white sands, and capped unconformably with gravels. 
On the west side of Bushy Creek the beds first of all strike north and dip 
to the west at high angles, about 75°; but when followed farther south 
across a small tributary coming in on the west the strike gradually swings 
round to north-east, and the beds dip south-east 45° and are apparently over¬ 
turned. This feature is clearly visible in the high sandstone bluff of the south 
side of the tributary, where the swinging-round and overturning of the 
beds are most marked. The disturbance is in all probability due to some 
major faulting movement which has affected the northern flank of Mount 
Torlesse, of which there is evidence in Iron Creek, as will be noted directly. 
This movement is perhaps partially responsible for the formation of the 
depressed area now constituting the Waimakariri intermontane basin. 
The higher beds occurring in Bushy Creek consist of sands which are 
slightly glauconitic in character, but the true greensands are not developed 
here, although they may occur under the covering of bush which mantles 
the slopes to the west and south of the creek. 
A study of the beds as they occur in Alum Creek gives a tolerably correct 
idea of the conditions under which the coal-measures were laid down. The 
fairly regular stratification of the lowest strata, followed by the irregularity 
of the middle beds, and the regularity of the stratification of the top beds, 
are just those features which would be met with in an estuarine deposit. 
The first series would constitute the bottom-set beds, the second the fore-set 
beds; but the last would hardly correspond to what are usually called the 
top-set beds, seeing that they must have been laid down in deeper water 
and with regular stratification. The passage of the upper beds into a green¬ 
sand certainly indicated deeper-water conditions. However, the two lower 
series exactly correspond to deltaic deposits. Thus we can explain the 
