140 E. O. Teecle: 



(3) Denudation of the existing cycle has developed to such an 



extent that a complex inlier is exposed, consisting of 

 a core of Cambrian rocks enveloped successively by 

 Upper lOrdovician, Silurian and Upper Palaeozoic sedi- 

 ments. 



(4) The Upper Palaeozoic strata are of lacustrine origin, and 



those of the other periods are marine. The Cambrian 

 limestones liave yfelded a definite series of trilobites, and 

 a-re i.nterbedded in basic tuffs. The Upper Ordovician 

 rocks are black slates, chertified in part, and they con- 

 tain aibundant typical graptolites. The Silurian rocks- 

 have so far only yielded crinoid remains. 



(5) Igneous activity is represented in two and probably three, 



distinct periods if we consider the district as a whole, in- 

 cluding the Upper Palaeozoic rocks as far as Mansfield. 

 'The Cambrian series contains a pre-Upper Cambrian ser- 

 pentine, with chromite and corundum derived from peri' 

 dotite and pyroxenite rocks, and the Upper Cambriart 

 •contains bas.ic tuffs. Volcanic rocks of the nature of ]X)r- 

 phyrites allied to dacites occur in the King River Valley, 

 and others, mainly of an andesitic nature, on Fullarton's 

 'Spur, in the IMacallister Valley. These are probably 

 Lower Devonian. The basal portions of the Upper 

 Palaeozoic (Lower Carboniferous), contain thick beds of 

 rhyolite, and acid pyroclastic deposits. Higher up in 

 the series there is a succession of basaltic flows (mela- 

 phyres) interbedded with the sediments. 



(6) Special structural features are noted along the Macallister 



valley, where the Uj^per Palaeozoic rocks, normally dip- 

 ping at a low ,a,ngle, are here frequently highly inclined, 

 and an important fault line is recognised, appi'oximating 

 in position to that of the Macallister Valley, and bear- 

 ing, therefore, in a N.N.W. direction. 

 2. The District of Xova Xou/t. 



(1) The cherts and jaspers of the region have been examined 

 with regard to age and the origin. All the cherts ob- 

 served are altered slates, and are regarded as Upper 

 Ordovician. Definite graptolites have been found in 

 . some of them. The red jaspers are often associated 

 with micaceous hematite, and are found chiefly in the 

 porphyroid belt of the " Snowy River Series," and are- 



