8 



obscured (on its western side) by deep soil and orchards, but 

 was proved in the well-sinking at the bottom of the valley, 

 and it can then be traced up on the eastern side to the prom- 

 inent ridge in which the old Montacute copper mine is 

 situated (Sec. 5584). This ridge is steeply truncated on its 

 northern side (probably a fault face), showing a scarp of about 

 200 ft. in .height. The section seen on this face, in ascending 

 order, is as follows : —r^^; slates, fhj strong quartzite, CrJ 

 thin slates, fd J blue limestone, ft-) thick slates. The quartzite 

 and limestone together make a bold, precipitous face. On the- 

 western edge of this scarp the limestone is very strong, with 

 a white crystalline texture, and has been quarried to a slight 

 extent. On the eastern side the limestone passes down to the 

 Sixth Creek in massive beds, and varies from a bluish, earthy 

 limestone to a white, marble-like rock. The country is much 

 disturbed and mineralized, and the limestone appears to have- 

 been locally altered under these special circumstances. 



The beds on the Montacute Mine hill have a general dip 

 to the south, at a low angle, but on the eastern side there is 

 a sharp downthrow to the east. On the old roadway that goes 

 up to the workings on the eastern side of the hill, above the 

 Sixth Creek, the quartzites have a dip south, at 50°. This is 

 immediately followed by a sharp pitch to the south-east, 

 which carries the limestone by a dip-slope down to the creek 

 below. The limestone here dips south-easterly, and as the- 

 strike accords very nearly with the direction of the creek the 

 former makes a spread of 130 yards. The limestone passes to 

 the opposite bank, a few feet above the creek level, and then- 

 disappears under the overlying phyllites (dip south-east, at 

 28'). This change of dip and strike at about the meridian 

 of the creek is probably accompanied by a fault. 



The Montacute Mine is located near the fault : or, perhaps,, 

 along the lines of a series of small faults. The development 

 of quartz veins and vein-stones, in addition to the change of 

 strike, suggests the presence of faults. Copper sulphides occur 

 freely in the vein-stone, and have been partially dissolved" aTicT 

 carried by percolating water through the adjacent slates and 

 quartzites, the coloijring of which by green carbonate films has 

 prompted much abortive prospecting in poor country. On 

 the eastern edge of the hill a long stope, open to the surface,, 

 has been worked along the angle of downthrow to the east. 



The limestone on the eastern pitch (which is best seen in 

 the gorge cut by the creek) has been considerably altered, 

 probably by mineral waters rising through the fractures. The 

 limestone has been changed from a bluish and earthy limestone^ 



