782 



THE GEXERAL GEOLOGY OF MARULAX AXD 

 TALLONG, X. S.W. 



By W. G. Woolnough, D.Sc , F.G.S., Assistant Lecturer in 

 Mineralogy and Demonstrator in Geology, University 

 OF Sydney; assisted by Senior Students in the Geological 

 Department of the L'niversity. 



(Plates Ixv.-lxix.) 



Contents. 



Page. 



iKTKODrcnox 7S'2 



Sedimentary formations — 



Ordovieiau ... ... ... ... ... ... ... 7S3 



Silurian ... ... ... ... ... ... .. 7S4 



Devonian 7S5 



Permo-Carboniferous 786 



Triassic 7SS 



Cainozoic 788 



ERUPrn'E ROCKS — 



Glenrock grano-diorite 789 



Granite-porphyry and dacite ... ... .... ... 790 



Basalt 792 



Petrolooy— 



Eruptive rocks 795 



Contact-rocks 799 



The physiography of this area has ah*eady formed the subject 

 of a paper by Mr. T. G. Taylor, B.Sc, B.E., and the author. In 

 addition to the interesting problems it presents in river-develop- 

 ment, the district is very remarkable for the variety of its rock- 

 formations. Within a radius of about six miles, we have 

 sediments of Ordovician, Silurian, Devonian(?), Permo-Oarbon- 

 iferous, and Triassic (1) ages. Intrusive rocks are represented by 

 a great boss of grano-diorite intersected by numerous aplitic 



