• 148 
A SYSTEM OF 
e. Dark grey, with white grains of feltfpa6 
alfo, from Guflavsftroin. 
Many varieties of this kind, in regard 
to colour, are found in form of nodules or 
ioofe ftones in Sweden •, but I have only 
mentioned the harded; and fineft of thofe 
which are found in the rocks becaufe, 
behdes thefe, there are coarfe porphy- 
ries found, which fcarce admit of any 
poiifh. The dark red porphyry has been 
mod; employed for ornaments in build- 
irfg : yet it is not the only one known by 
the name of PcrfJo^ the Italians apply- 
ing the lame name alfo to the black 
kind. 
SECT. CCLXyil. 
r. The Prapp of the Swedes, Saxum compofu 
turn jafpide martiali molli^ feu argilld mar-, 
tiali indiiratd^ et - - - - 
This kind of ftone fometimes cond-itutes 
or forms whole mountains*, as, for example, 
the mountain called Hunneberg, in the 
province of Weftergottland, and at Dram- 
men in Norway*, but it is oftener found in 
form of veins in mountains of another 
kind, running commionly in a ferpentine 
manner, contrary or acrois to the direction 
of the rock itfelf. it is not homo.geneous, 
as may be plainly fcen at thole places 
where it is not preded clofe together *, but 
where it is preiTed clofe, it feems to be 
perfeflly free from heterogeneous fub- 
iftances. When this kind is very coarfe, it 
is interiperfed wddi feltfpat *, but it is not 
knpwm if the finer forts like wife contain 
any 
