BY H. I. JENSEN, D.SC. 157 



and Early Devonian were of granitic magma : by the 

 same course of argument, we can suggest from the fine 

 grained and dark nature of the slates of the early Silurian 

 that the eruptions of that age and of the Ordovician 

 were of basic magma. 



Carboniferous. 



In the Carboniferous period, the movement of the 

 shoreline to the east was further accentuated. Along 

 great stretches the area of maximum sedimentation lay 

 far to the east of the present Continent. {Fig. 6). Isolated 

 or semi-detached seas covered the New England area of 

 New South Wales, and the Gympie area of Queensland. 

 Great uplifts, accompanied by granitic intrusions, took 

 place in the areas of maximum Silurian and Devonian 

 sedimentation. Mountain building was in this period 

 the result of earth folding processes, as instanced by the 

 gigantic earthfolds in the Devonian beds underlying 

 horizontal Upper Marine, near Braidwood, New South 

 Wales. 



A north and south running strip of the West Australian 

 Continental mass was lowered sufhciently to become the 

 depository of marine sediments. 



During this period and the following, it is not unlikely 

 that portions of Australia were connected with New Zealand, 

 Piji, and New Caledonia. 



Permo- Carboniferous. 



In the Permo- Carboniferous a shallow sea developed 

 to the east of the main Devonian areas {Fig. 7), running 

 north and south from the Sydney basin to the Dawson 

 River in Queensland. This elongated basin was probably 

 produced by folding, accompanied by faulting. In it 

 were deposited the Permo- Carboniferous beds. This basin 

 lay between the Gondwana land proper and the island 

 -continent between Australia and Fiji and New Zealand. 

 It stood to these two landmasses in the same relation as 

 the Sea of Japan does to Japan and China. It afforded 

 ^ means for floating ice to be carried far to the north. [4] 



Mighty upheavals took place in the Carboniferous 

 a,nd Permo-Carboniferous periods. Such elevated lands 

 were built up that mammoth glaciers shed icefloes, which 

 not only found their way far to the north in the South 



