572 



2. The Great Western Fault. 



The main fault on the western side of Mount Remarkable 

 appears to be coincident with the bed of the Spring Creek, 

 extending from the headwaters of the latter to the Spring 

 Creek mine, and possibly further north. Spring Creek pursues 

 a remarkably straight course. When standing on its watershed 

 and looking down the valley, it has the appearance of an 

 artificial ditch. It has no projecting spurs and scarcely a 

 curve in its course (see map) — a physical feature that is 

 strongly suggestive of a line of faulting. It is true that the 

 bed of the creek follows the junction of dissimilar rocks along 

 their line of strike, but this is scarcely sufficient to explain 

 its remarkable straightness for a distance of five miles. 

 Definite evidence of an important fault on this line is obtained 

 by the gradual narrowing of the tillite outcrop and its final 

 disappearance before reaching the northern end of the mount. 

 The tillite is here cut out by a strike-fault*, and the Tapley 

 Hill shales are brought into direct juxtaposition with the 

 quartzite, making a strong stratigraphical unconformity. 



It is possible that this fault-plane is continued southward 

 beyond the limits of the Spring Creek Valley. The Mount 

 Remarkable Creek runs for the distance of a mile in a straight 

 course on the dividing line between the Tapley Hill slates 

 and the tillite (precisely similar to the course of the Spring 

 Creek), and the tillite narrows into almost nothing in its 

 southern extremity, where it abuts upon and ends at the 

 transverse fault at the southern end of the mount — features 

 which are similar to its disappearance by faulting at its 

 northern extremity. 



3. The Great East and West Fault at the Northern End 



of the Mount. 



The main fault at the northern end of the mount (which 

 appears to possess a strike a little north of west) truncates 

 the quartzite of the main ridge, for the latter cannot be seen 

 north of that line, and its place is taken by beds that are 

 higher in the series. Notwithstanding the magnitude of this 

 displacement the immediate zone of fracture cannot be seen 

 on account of the great spread of quartzite talus that 

 encumbers the northern slopes of the mount and even en- 

 croaches upon the road, and thereby hides from view the 

 immediate fault-plane. The main road that crosses the end 

 of the mount is very near the fault, and in some of the 

 small cuttings on the road there are evidences of strati- 

 graphical disturbance that show its close proximity. 



After passing the highest point on the road (immediately 

 to the west of the main limestone outcrop) the purple-slates 



