STRATA of the GRAMPIANS. 15 
fuch junctions are always to be much Bartee in mineralogical 
refearch. 
Havine paffed over this narrow plain, I advanced towards 
a fecond range of hills, which here form the bafis of the central 
and higheft chain. It is at this place where the river fo fud- 
denly changes its courfe from eaft to fouth, and where I was un- 
der the neceflity of leaving its bed, to continue my northern di- 
rection towards Mount-Battoc. This, however, I was enabled 
to do to great advantage, by following up the deep cut bed of a 
winter torrent, which led me into the direction which I withed 
to follow. 
Upon entering the bed of this torrent, I found that the bafis~ 
of the hills here entirely confifted of micaceous fhiftus, much 
veined with quartz, and much twifted in its texture. The 
ftretch of this rock is here nearly from welt to ealt; and it has 
a foutherly dip of 45 degrees. 
In pafling through among thofe hills towards the central 
range, I found in feveral of the beds of the torrents large blocks 
of reddifh-brown porphyry, with {cattered maffes of micaceous 
fhiftus and granite. 
In tracing up one of thofe torrents, I faw the micaceous-fhif- 
‘tus rock and the porphyry both expofed to view,’near to each 
other ; and, foon after, in the bed of the fame torrent, I came to 
a cafcade which had laid bare both thofe rocks at a point where 
they are in contact ; and near thofe a fecond bed of porphyry 
" made its appearance, in the front of a near hill. From my firft 
view of thofe, and from their relative pofitions, I was led to ima- 
gine, that they might here alternate in vertical pofition ; but up- 
on more minute infpection, I found that the porphyry conftituted 
vertical dikes, ftretching nearly from fouth to north ; which courfe 
cuts the line of direction of the Grampians here almoft: at right 
angles : and, on the contrary, I found that the micaceous fhiftus 
which. flanked thofe dikes of porphyry, had a regular ftretch: 
from.: 
