558 



spread, and at the top of the hill they have a dip which is 

 practically at 90°. Some mineralization has occurred in 

 places (chiefly specular hematite), which has tempted the 

 prospector to put in some exploratory work, and near the 

 summit, in a particular zone of these limestones, a curious 

 segregation of quartz has taken place, making hollow 

 spheroids, giving the rock the appearance of a "pea-stone" or 

 pisolitic structure. 



While the main limestone maintains a moderately direct 

 course to the southward, the underlying impure limestones 

 describe a curve, following the right bank of the creek, and 

 at a distance of half a mile higher up from their first crossing 

 they recross the creek to its western side. In this latter case 

 they strike the creek diagonally and make a striking feature 

 in the bed of the stream, where the limestones exhibit some 

 remarkable contortions and have weathered into irregular 

 masses and outlines that make picturesque features. The 

 erosive action of the stream is also well illustrated by deep 

 gutters, smoothed surfaces, and pot-holes. One of the latter, 

 with one of its sides worn away, is known locally as the 

 "Armchair." 



The limestones at this spot occupy the banks on both 

 sides of the stream, but gradually curve round to the west, 

 in a direction almost completely opposite to their strike in the 

 first instance, and after rising on the back of a spur to the 

 top of the ridge make a slight curvature to the south, where 

 they are cut off by the main fault that separates the foot hills 

 from the mount proper. The outermost line of outcrop of 

 these limestones meets the creek at right angles, with a strike 

 W. 20° N., dip northerly at 78°. This limestone was seen to 

 cross the stream to the westward, but could not be recognized 

 on the opposite bank. 



b. UPPER CAMBRIAN. 



Purple-slates Series. 



The belt of limestones described in the preceding sections 

 forms the upper limits of the Lower Cambrian Division of 

 rocks. The beds that follow by sequence and in super- 

 position possess, as a series, characteristic features, and are 

 classed as Upper Cambrian. They consist of thick shales, 

 numerous thin layers of quartzite, arenaceous limestones, and 

 at some horizons develop thick, fine-grained quartzites that 

 are usually subdivided by numerous bedding-planes. The 

 beds possess a characteristic bluish or purplish colour, on 

 which account they have been designated the purple-slates 

 series. They are extensively developed in the region now 



