122 The Sedimentary, Metamorphic, 



The sedimentary crust of the earth in Gippsland was sub- 

 jected to such conditions as those I have just referred to at 

 the close of the Silurian age, and they imply pressure, heat, 

 mineralised waters, and vast periods of time, in fact all that 

 which is requisite, so far as we know, to produce meta- 

 morphic action and mineral regeneration. 



It appears to me to be very significant, when looked at 

 from this standpoint, that the most crushed and contorted 

 rocks in the Gippsland Alps are to be found in the area of 

 regional metamorphism ; in other words, where the sediments 

 have been most dislocated and compressed, there it is that 

 metamorphism has been most intense. 



According to these views, the mineralisation of the 

 argillites and the regional metamorphism of the sediments at 

 Ensay and Omeo are respectively earlier and later stages of 

 the same process, which, for want of a better term, might be 

 spoken of as dynamical metamorphism in contradistinction 

 to contact metamorphism. 



These views lead to the further conclusion that places 

 such as Ensay, wherein the sediments have been converted 

 in limited areas into mica schist and gneiss before their in- 

 vasion by the plutonic rocks, were localities in which the 

 movements of the strata were greatest, where the tempera- 

 ture was consequently higher than elsewhere in the distorted 

 crust, and where, as a direct consequence, metamorphism 

 reached extreme stages. 



Moreover, it seems to me to be quite conceivable that, under 

 such conditions, those localities would be most readily in- 

 vaded and absorbed by the plutonic rocks if the invasion 

 was part of the same great range of operations. 



As I see the evidence to be obtained in the Ensay district, 

 dynamical metamorphism — as I have definedit — first produced 

 an alteration of the sediments to the condition of argillites, 

 next to phyllites, and finally to mica schist and gneiss. 



The schists then being invaded by the plutonic masses 

 were no doubt further affected by contact metamorphism ; 

 but in what manner, or to what degree, I am not at present 

 in a position to state. Possibly some further light may be 

 thrown upon this very obscure subject by work which. still 

 remains to be done as regards the Omeo district. 



I have now briefly stated the hypothesis which I have 

 ventured to bring forward as explaining the seeming 

 anomalies of the Ensay schists. The belief that the crushing 

 together of the strata has produced sufficient heat to set up 



