HujJihiiuh of Western Victoria. 257 



nite area-s to the south ; they probably have never extended 

 across the present highhmds. If the surface had been made 

 almost fla/t- the appearance of granites on the peneplain would be 

 simply a question of the level re«ched by the granites. This 

 would depend partly on the level it originally reached at tho 

 time of its intrusion, and partly on later movements, whicli it 

 might sha/i'e with adjacent sediments. The granitic rocks of 

 Victoria do not as a rule appear in well marked axial lines, but 

 in places they show verv straight boundaries on the peneplain ; 

 the south edge of the Mt. Cole granite in the Pyrenees is fn 

 example, though on the map the straight boundary is obscured 

 by the accumulation of detritus at the mouth of a short valley. 

 A fault had probably already existed w'hile the peneplain Avas 

 forming, and the more elevated granite to the noi-th had been 

 exposed by denudation. On its northern boundary this granitic 

 area meets the sedimentary and metaniorphic rocks on irregular 

 lines. A similar explanation might be given of many other 

 granitic boundaries in Victoria. Sehvyn had already in 1857 

 referred to a fault line on the east coast of Port Phillip, making 

 the boundary of the granitic areas there. - 



We have not only to consider in connection with the positions 

 occupied by granites, the height to which they were brought 

 at the time of their intrusion, but also the subsequent move- 

 ments as inert masses. In the formation of the peneplain it is 

 evident that a point of maximum elevation is a point of maxi- 

 nmm denudation, and consequent more probable exposure of 

 deep seated rocks. On the other hand the downthrow side of 

 a fault is, other things being equal, a jDoint favourable for the 

 preservatidn of the newer and more superficial deposits. This 

 may have been the reason of the survival of a small glacial area 

 at the Midas mines- north of Ballarat. Messrs. Othcer and 

 Hogg'' have also described the glacial rocks as terminating north 

 of Coimaidai at ai steep bank of Ordovician rocks, and though 

 they regard it as a pre-existent valley wall, it seems to me that 



1 See Hall and Hritclianl. Some Sections Illustrating the (leolojirical Stniotuve of the 

 Country about .Moriiinj,'-toii. I'roe. Hoy. Soe. Victoria, XIV., pt. I., Xew Series. 



2 K. .1. Dunn, Notes on the (Macial Conglomerate Wild Duck Creek, Depaitment of 

 Mines, .Mcll)oiiiia', lSi)2. 



3 Pioc. l{oy. Soc. Victoria. .\., lit. 11.. Xew Series, 18!)S. 



