REPORT OF THE DIRECTOR I920-2I 103 



nearly the whole of the. western half of the continent, outcrops in 

 northeast Queensland, forms the foundation of southern New South 

 Wales and eastern Victoria, and is exposed in western Victoria, in 

 Tasmania, and in the western flank of the southern Alps of New 

 Zealand. These areas of Archean rocks were doubtless once con- 

 tinuous. But they have been separated by the foundering of the 

 Coral sea and the Tasman sea; and the foundering of the band 

 across Australia from the Gulf of Carpenteria through western 

 Queensland, and western New South Wales, to the lower basin 

 of the Murray has separated the Archean areas of eastern and 

 western Australia." The entire southwestern and western areas 

 of the western moiety of the continent consist of granite and gneiss 

 with overlying metamorphic schists and a belt of Paleozoic rocks 

 along the west coast. The folds of western Australia are described 

 as running north and south with a slight trend to west (Encycl. 

 Brit., ibid.). Suess (v. 2, p. 259) states that these folds are convex 

 toward the east and Maitland (19 17) describes the coastal region 

 as being affected by Prepermian Carboniferous folding. (H. P. 

 Woodward thought they were Devonian, but this can not be proved 

 in the absence of fossils.) These folds, however, run conformable 

 to the trend of the Precambrian strikes and may therefore be well 

 considered as of posthumous character. This is especially suggested 

 by the fact that the north-south strike of the Precambrian basement 

 complex apparently continues throughout the west of Australia 

 and reappears from under the Mesozoic and Tertiary strata of the 

 Nullarbor plains in the metamorphic rocks of southern Eyre peninsula 

 in south Australia (Tilley, 1920, p. 450). Tilley considers this 

 latter region expressly "as a southeasterly prolongation of the 

 great Precambrian shield of western Australia." These meta- 

 morphic beds (gneisses, schists and quartzite dolomites) of Eyre 

 peninsula strike in a north-south direction, with a high angle of 

 dip to the west (75 to vertical). 



Eastern Australia and Tasmania are traversed by Cordilleras 

 that are the result of late Paleozoic folding, but also there folds 

 show nearly everywhere a meridional strike (see Suess, v. 2, p. 194), 

 except in the north, in Queensland, where it changes to north-north- 

 west; then to northwest-southeast and finally to west-east (see 

 Encycl. Brit. v. 2, p. 732). 



Like Africa, Australia is a crystalline massif that has acted as a 

 solid block and been invaded by later folding only in the western, 

 southeastern and eastern marginal region's. The Precambrian folding 

 appears like that of Africa to possess a prevalent north-south trend 



