Palaeozoic Geology of Victoria, 135 



teither successively or simultaneously, it Avould be reasonable to ex- 

 pect complex and apparently anomalous results with regard to the 

 associated igneous activity. Summers (33) has reviewed the rela- 

 .tionships of igneous rocks to earth movements in Victoria, and has 

 opened up an extremely interesting, but very debatable subject. 

 He has, however, shown that it is impossible to apply Marker's 

 .generalisation. It is practically certain that if the various geologists 

 who are sufficiently familiar with the local geology were to attempt 

 to make out a picture of the Palaeozoic history with special refer- 

 ence to the associated earth movements, they would differ consider- 

 ably in important details. One or two events, however, stand out 

 very clearly, and it is probable that all would agree with the view 

 that the opening of the Devonian epoch was marked by most ener- 

 getic earth folding, which intensely crumpled all the already folded 

 pre-existing formations. 



As Summers pointed out, the dominant movement was of the 

 pacific type along north and south fold lines, but was it accom- 

 panied by great volcanic and plutonic activity, as has generally 

 been believed? It would j-ather appear that the igneous phase, 

 though related with this great crustal disturbance, lagged behind 

 somewhat, otherwise, we might reasonably expect to find a definite 

 linear arrangement or relationship of the igneous rocks, with some 

 of the major fold lines. This is far from the general rule, how- 

 >ever, in fact it is only in the case of tho '' Snowy River Porphyries " 

 that a meridional arrangement is apparent. All the other occur- 

 rences appear to be distributed in a very irregular manner. Fur- 

 ther, the volcanic deposits would appear to rest unconformably on 

 the upturned edges of the older rocks. It appears to be the excep- 

 tion that the ash beds are intensely folded with the older beds. 



Summers (33) has also discussed the question of the Heathcotian 

 'diabases and earth movement, and favours the idea that tlie basic 

 •eruptions and submarine tuffs of the Heathcotian Series are more 

 -easily explained as accompanying fault action rather than fold 

 movement. It must be admitted, however, that the evidence is very 

 scanty and indefinite, and is open to be interpreted in either way. 

 The area exposed is far too limited, and the structure too imperfectly 

 known to enable any satisfactory criticism to be made. 



The Granite BathoUths and their Relation to Pakieozoic Structure. 

 No account of Palaeozoic liistory wouhl be complete without 

 some special reference to the abundant jzranite masses which i)ene- 

 trate the Lower Palaeozoic sediments. 



