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Onkaparinga at 80°. On the east side of the fault the lime- 
stone dips east-south-east at 80?, being overlain by the sili- 
ceous limestones which dip in the same direction at 70°. The 
fault is, therefore, the result of an overthrust from the east, 
which has fractured the beds, and given a reversed position 
to the limestone, and placed the lower beds in a superior 
position. 
The limestone has a strong outcrop as it passes over the 
hill into the next gully, to the south-west, where it has a 
dip west, 20? north, at 80?, and is cut out at the intersection 
‘of dip fault (D) with the main strike fault (C). 
Still travelling south-west, two dip faults (the one just 
mentioned (D); and another (E), about 250 yards distant), 
run from the strike fault (С) in an easterly direction. The 
result is a downthrow, by which a wedge-shaped strip of 
purple slates is introduced, and cuts off the limestone beds 
both on the northern and southern sides of the strip. 
Further strike faults are developed from each of the two 
dip faults just referred to. On the east side of the district 
road (which crosses the river at the Ford), and near the top 
of the hill on the southern side of the river, a strike fault 
(F) can be seen in a small gully which connects with Long 
Gully. This fault crosses the latter obliquely, and follows 
a line nearly parallel with the Onkaparinga. On the west 
side of the fault there are two small pockets of limestone. 
as outliers, preserved by a downthrow to the fault, one on 
either side of the valley. The southerly patch dips south, 
at 23^, with a roll to the south-east. The east side of the 
fault is occupied by purple slates which dip west, 10° north, 
at 38°. The fault plane is very strongly marked as it; 
crosses another tributary, on the east side of the valley, near 
the mouth of Long Gully, with purple slates on one side, and 
the impure siliceous limestones on the other. 
Parallel with the fault just described is another strike 
fault (G), about a quarter of a mile further to the east, 
which brings in the limestone once more at an angle of the 
creek. To the south the limestone is cut off by the dip 
fault (D), and, together with two repetitions of the same 
bed, is cut off on the north side by dip fault (T). Where the 
limestone crosses Long Gully the beds are vertical, whilst 
the purple slates, on the west side, dip west at 70°. The 
junction of the limestone with the purple slates, along the 
fault plane, is marked by a powerful spring which issues 
from the limestone in Long Gully, and yields a constant 
supply of running water in the creek, which is not affected 
by the seasons. This is an excellent illustration of a fault 
spring, the subterranean water in the calcareous beds on 
