598 GREAT SERPENTINE BELT OF NKW SOUTH WALES, viii., 



Devonian rocks of this region are so remarkably little altered, 

 for rocks east of the main Serpentine-line, as to indicate some- 

 what different conditions from those which have prevailed in 

 the districts north of Nundle. In either case, it is probable 

 that the Serpentine-line will eventually be traced from Nundle 

 down to the coast, thus adding another hundred miles to the 

 hundred and fifty already mapped, and thus forming one of the 

 most continuous structural lines in the State. 



A few words may "be given with respect to the serpentines of 

 Port Macquarie, which were described by Mr. Carne(16). In 

 this region, the predominant strike is to the N .N.E. It has been 

 suggested that the serpentines here lie on the same line as those 

 of the Great Serpentine Belt, which has swung round from the 

 S.S.E. to the S.E., and eventually into the N.N.E direction, 

 and thence swings further round to include the serpentines of 

 the Clarence River, recorded by Professor David and others(17). 

 The Serpentine-line, on this hypothesis, forms a discontinuous 

 ring about the strongly compressed Permo-Carboniferous rocks 

 and the great granitic masses of north-eastern New South 

 Wales(18). The writer has pointed out, however, that the pre- 

 sence of a N.W. to N.N.W. strike so close to the coast as the 

 Gloucester District renders this suggestion improbable, and in- 

 dicates rather that the Port Macquarie N.N.E. line of strike is 

 more likely to be on a virgation passing off from the main N.N.W. 

 direction. Several such virgatious have been noted between 

 Binsara and Nundle, notably at Mundowev on the Namoi 

 Pviver(19), though they have not been traced into a greater 

 divergence from the main direction than a N.-S. line of strike. 

 Such an hypothesis, however, involves a much simpler distribution 

 of folding forces than that necessary to explain the discontinu- 

 ous ring of intrusions, though the latter would not be entirely 

 without analogies. A comparison, though an extremely strained 

 one, might be made with the discontinuous line of serpentine- 

 intrusions around the Central Granite of the Austrian Tyrol, but 

 it is very doubtful whether such a comparison would indicate 

 any real analogy, so diverse are the other features in the two 

 areas ( see 20) . 



