559 



under description and form an outlying and investing circle 

 of outcrops around Mount Remarkable. 



(a) THE WESTERN OUTCROPS. 



The hills on the western side of Spring Creek rise in a 

 steep grade to the watershed of the Black Range. The 

 geological section in this direction is comparatively simple : 

 the Tapley Hill slates occupy the slopes next the creek, and 

 are succeeded, in ascending order, by the siliceous limestones 

 — the main limestone. — and the purple-slates series. The 

 latter follow a parallel strike with the limestones in a north 

 and south direction. The lower members of the series consist 

 mainly of slates and thin-bedded quartzites ; but in the Black 

 Range, which forms the greatest elevation on that side of Mount 

 Remarkable and overlooks the littoral of Spencer Gulf, they 

 pass up into strong and prominent quartzites, which make the 

 main feature of the range. 



(b) THE NORTHERN OUTCROPS. 



The purple-slates series on the northern side of the mount 

 has participated in the block-faulting that has so greatly dis- 

 turbed the limestones and other underlying beds. The 

 prevailing dip of the limestones is to the westward, but 

 occasionally to the northward, and the purple-slates, which 

 follow next in order, conform to the same general dip — either 

 westerly or northerly, according to the pitch of the faulted' 

 segment to which they respectively belong, the prevailing 

 direction being westerly. 



In ascending Spring Creek from the Wilmington Road 

 the purple slates make their first appearance immediately 

 on the western side of the top or main limestone seen in the 

 creek, about a mile up from the main road. Here the beds 

 dip W. at 40° and follow the strike of the limestone south- 

 ward to the road that crosses over to the Spring Creek mine. 

 Higher up the creep, just above the weir of the Wilmington 

 water supply, the purple slates are very characteristically 

 developed, forming extensive dip slopes to the creek; dip, 

 W. 10° N. at 40°. 



The beds continue to occupy both sides of the creek, and 

 can be followed up the White Mine Creek and the Waterfall 

 Creek, which unite and form a junction with the Spring Creek 

 at the position selected fo'r the new reservoir. In the lower 

 portion of the White Mine Creek bluish quartzites and sili- 

 ceous slates make a feature, having a dip W. 10° N. at 48°. 

 Higher up the creek characteristic purple-slates are more in 

 evidence. 



