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Granite^ Quartz-rock, and Red Sandstone. 
View is still maintained by some mineralogists, but must ere 
long be abandoned, as it is now known that granite is associated 
with many different kinds of strata. 
Granite occurs in great imbedded masses, and veinSj in sye- 
nite. These masses, often many fathoms in extent, at their line 
of junction with the granite, are sometimes simply attached, 
more frequently appear intermixed with it, or pass into it, and 
branches or veins shoot from the granite into the syenite. 
Porphyry, a very widely distributed rock, sometimes con- 
tains imbedded masses and veins of granite, in which we have a 
repetition of the same phenomena as observed in the masses in- 
closed in syenite. But many porphyries are mere varieties of 
granite, in which the base is very fine granular granite. 
Granular foliated limestone, in primitive mountains, is some- 
times traversed by veins of granite, or contains imbedded mas- 
ses of that rock. 
Gneiss, Mica-slate, Clay-slate, and Grcy-wacke, are frequent- 
ly traversed by veins of granite, and in many districts there are 
whole hills and ranges of hills, which are the outgoings of im- 
bedded masses, and beds of granite, situated in the rocks just 
enumerated. But these are not the only rocks which contain, 
granite ; for immense imbedded masses, beds, and veins, occur in 
quartz-rock, and also in the red sandstone connected with that 
interesting formation. 
This concise enumeration of facts, proves, that granite is not 
confined to one particular species of rock, but occurs in many, 
and that it is not of earlier formation than all other rocks, nor 
of newer formation than most others, but is very often a co- 
temporaneous crystallization with the rock in which it is si- 
tuated. 
II. — Geognostical Relations of Quartz-Rock. 
Werner was the first naturalist who studied the geognostical 
relations of this rock, and his view is stated in my Elements of 
Geognosy. I have traced its distribution in the mountainous 
districts of the Highlands, and the same has been done by my 
active and acute friend Dr MacCulloch. We have ascertained 
that its relations are much more varied than was formerly be- 
.lieved, and that it occupies a greater portion of th^ Q,l:ust of th^ 
VOL. I, m I. 1819. 
