^88 • H. S. Summers : 



chain of the Andes, but it is difficult to imagine such earth move- 

 ments giving the requisite conditions for the production of inter- 

 bedded submarine lavas and tuffs. While the evidence is not at 

 all conclusive, I believe that the basic lavas of the Lower Ordovician 

 were associated with fault movements and, according to Barker's 

 generalisation, should show alkaline affinities. 



(b) Ujyper Palaeozoic Series. 



The intrusion of the granites and granodiorites and the associ- 

 ated volcanic rocks are undoubtedly associated with the intense 

 •earth movements to which the Ordovician and Silurian formations 

 have been subjected. In the Macedon District (19) we have 

 ■evidence of extensive earth movements subsequent to the deposition 

 of the Lower Ordovician and prior to the deposition of the Upper 

 Ordovician. The Kerrie Conglomerates have been shown to belong 

 to the Upper Oi'dovician, and there is apparently a strong uncon- 

 formity Ijetween these conglomerates and the underlying Lower 

 Ordovician. The base of the Silurian is also marked by basal con- 

 glomerates, and the rocks of this system are in general less 

 folded that those of the Upper Ordovician, so we may fairly safely 

 infer considerable earth movements as marking the break between 

 these two great periods of sedimentation. In the eastern part of 

 Victoria Dr. Howitt (9) has shown that the Lower Devonian was a 

 period of great igneous activity associated ^vith intense earth 

 folding. The Mansfield sandstones of Upper Devonian or Lower 

 Carboniferous age rest unconformably on the upturned edges of 

 the Silurian. 



Folding over north and south axes was the prevailing type of 

 tectonic movement to which the Ordovician and Silurian sediments 

 were subjected, so that we can safely infer that the granites, grano- 

 diorites, dacites, etc., were associated with movements of the 

 Pacific coast type. 



(c) Kainozoic Igneovs Series. 



The Victorian basaltic rocks are certainly not associated with 

 fold movements, because throughout the Kainozoic Period in 

 Victoria there is no evidence of any earth movement of this type 

 ■except of a purely local character. On the other hand there is 

 abundant evidence of Kainozoic faulting. I understand that Mr. 

 D. J. Mahony is working out the evidence of this Kainozoic fault- 

 ing, so that I will not enter into the subject at any lengtli. The 

 first record of Kainozoic faulting is due to Selwyn (13), who pointed 

 out the fault line along the eastern shore of Port Phillip. In 

 South Gippsland there is abundant evidence of post-Jurassic fault- 



