1815.] Transactions of the Geological Society, Vol. II. 63 
confound the primitive, transition, and floetz rocks, and to abolish 
all distinctions whatever. Such gradual transitions might have 
been expected, and indeed were previously well known. 
XIX. Remarks on several parts of Scotland which exhibit Quartz 
Rock, and on the. Nature and Connections of this Rock in general. 
By Dr. Macculloch.—Our indéfatigable mineralogist describes, in 
the first place, the mountains of Jura, which are chiefly composed 
-of a granular quartz. He endeavours to show that this quartz is in 
reality a sand-stone formed of disintegrated granite: that it some- 
times contains clay, sometimes rounded grains of felspar, and some- 
times rolled masses or pebbles of quartz itself. No mode of rea- 
soning is more apt to lead into mistakes than this. And I am 
strongly inclined to believe that on the present occasion Dr. 
Macculloch has misled himself by his own ingenuity ; at least 
no specimen of this rock which I ever saw contained a single 
true fragment, or gave any evidence that it was any thing else 
than true granular quartz. He then gives an account of the 
quartz rock Which occurs in Sutherlandshire, at Schihallien, and 
in several other places. In all these, according to him, it is exactly 
of the same nature as at Jura. Nowat Jura it is covered by mica- 
slate; therefore mica-slate, he infers, is of later formation than 
sand-stone, and consequently ought to be struck out of the list of 
primitive rocks. This mode of reasoning is not accurate. Quartz 
rock occurs in primitive, transition, and floetz formations, provided 
the old red sand-stone be included under it. Primitive quartz rock 
is not a sand-stone, but a granular quartz; so is transition quartz 
rock ; but floetz quartz is a true sand-stone, at least in many cases. 
Primitive quartz rock forms beds in mica-slate as in Jura, in gneiss 
and granite in Braemar, in mica-slate in Schihallien, in clay-slate 
in Beniwhone. It occurs also in grey-wacke. It occurs in the 
coal formation, and among the floetz rocks. In this respect quartz 
rock agrees with lime-stone, trap, porphyry. ‘here is nothing 
wonderful in finding this recurrence. Nor does it militate in the 
least against the doctrine of formations, or the division of rocks into 
primitive, transition, and floetz. ‘That division is founded entirely 
upon petrifactions. None exist in primitive. They exist in transi- 
tion rocks; but only the lowest classes of vegetables and. animals 
are found in this position, The floetz rocks contain  petrifactions 
more similar to the living beings that now exist ; and this similarity 
increase$ as we descend in the series. . Remove these grand distinc- 
tions, and the whole doctrine of rocks is plunged into confusion. 
Retain them, and the whole is clear. When the same rock occurs 
in different classes, we have only to apply to it the name of the: class 
in which it is found to keep every thing distinct: and we have’ only. 
to abstain from applying the observations which we make upon a 
rock when it occurs in one class to the same rock when it occurs'in 
another class, to prevent our falling into mistakes, and drawing 
absurd consequences. 13 
» XX. Notice relative to the Geology of the Coast of Labrador. 
