BY W. X. BENSON. 539 



of the aiidesites, and extends from there to the Green Slate zone 

 (fig 4). It is also developed at the Oaloola Gold Mine on the 

 east side of the creek, and has been here brought into contact 

 with the Augen Slates. This, I believe, is due to the existence 

 of a fault as suggested previously (p. 535). 



The Oxidised Slate is the final product of the oxidation of the 

 Blue Slate. At Caloola this zone of oxidation extends down 

 below the level of the creek-bed In hand-specimen it is crumbly, 

 soft and silky to the touch, and yellowed with limonite. Fre- 

 quently it is recemented near quartz veins, and forms a hard 

 rock. At Caloola it contains large limonite pseudomorphs after 

 pyrites, usually in cubes, but occasionally dodecahedra; on the 

 andesite boundary it is coloured a deep red with haematite 

 derived from the andesites.'^ At this latter point it is soft and 

 friable to a depth of 40 feet, and has lost cleavage and 

 stratification. 



The second group is termed Quartz Schist, and there is but 

 one occurrence known to me. It is at Caloola, where it forms 

 the wall of the fault before described. In hand-specimen it is a 

 hard, lustrous, pink and white streaked slate, like shot silk, with 

 a fair cleavage and very fine grain. Microscopically it is almost 

 entirely quartz in very fine grains, cemented by films of haematite 

 and limonite. Sericite occurs in long parallel fibres, and some 

 rutile. Zircons are included in the quartz grains. Rock- 

 flowage structure is not well developed. 



From the field-occurrence as well as from the appearance of 

 this rock, I am inclined to believe it is a rather sandy slate which 

 has been crushed during the faulting. 



The third group is termed Augen Slate, a name suggested to 

 me by Dr. Woolnough. It occurs typically near the limestones of 

 Caloola, where it forms a broad band running approximately north 

 and south; it also occurs in the hill between Newbridge and the 

 granites crossing the railway in a band 50-60 yards wide, running 



* J. B. Jaquet, " Iron Ore Deposits of New South Wales," p. 26. 



A R Y I 



