Palaeozoic Geology of Victoria. IIV 



The rocks througlioiit the gold field, iiiv addition to their sheared' 

 features, are frequently somewhat cherty, and on the whole are light-- 

 coloured, varying from whitish to creamish, with some superficial 

 ironstaining along the joints and bedding planes. This light 

 colour may be due to extensive bleaching within the zone of 

 oxidation, for occasional loose fragments of black chert are to be 

 found, and there is one occurrence of black chert in situ in the bed 

 of Lady Torr Creek. 



Special attention was given to the region of the old gold mines, 

 because it was here that Mr. E. J. Dunn described the occurrence 

 of " Heathcotian " (24), as well as Ordovician. Mr. Dunn observes 

 that "the Tara Range is remarkable that within a mile of the 

 Micaw^ber lease there are three distinct series of rocks carrying 

 auriferous vein-stones." 



The three series referred to are Heathcotian, Ordovician and 

 Lower Devonian, and the separation of the first two series appears 

 to be based on lithological differences only, particularly the supposed 

 significance of cherts and jasperoid rocks as a distinctive character- 

 istic of Heathcotian; but here again, as in the Wellington district 

 and elsewhere, this feature loses its significance, for at locality 6, 

 north of Lady Torr's Creek, the author found Upper Ordoviciai? 

 graptolites in light coloured cherty rocks, and in general these 

 rocks are so intimately associated with the more normal sediments, 

 which also yield Upper Ordovician graptolites (locality 18), that 

 there is no valid reason for separating them. 



Turquoise. — A little turquoise was found in an old adit in the 

 basin of Lady T'orr's Creek. It occurs chieflv along the joints, 

 irregularly distributed in a light-colored felspathic sandstone, 

 and though of interest as another example of its wide distribution 

 in the Ordovician, the specimens obtained did not afford much 

 promise from a commercial point of view. 



Gossnny Ironafoiie. — Towards the northern end of the area under 

 consideration (Fe 6 on map), there is an ironstone outcrop, consist- 

 ing chiefly of limonite. It is roughly elliptical in shape, measur- 

 ing about 3 chains in a north and south direction, and H to 2 

 chains across. Much of the limonite is hard and massive, but 

 some contains quartz, and broken up sedimentary rock. The limits 

 are rather indefinite, the deposit passing out into fei-ru^Mno\is shale 

 much crushed and jointed. The strike of the strata is' alx)ut 

 N.N.E., and the dip appears to be easterly at a high anirle. Another 

 similar outcrop occurs about 30 chains to the S.S.W., on the fall to 



