110 Professor Jameson cm the Geognostical Relations 
aspect, and rolled masses in these rocks, are the circumstances 
principally adduced in support of this hypothesis. But gra- 
nite is often arenaceous, and yet it is admitted to be a chemical 
formation, and no authentic rolled masses have ever been de- 
tected in quartz-rock, or in the red sandstone which is associat- 
ed with it. We must therefore abandon the mechanical forma- 
tion of quartz-rock and red sandstone, and inquire if they are not 
products of crystallization. In all rocks universally admitted 
to have been formed by crystallization, such as granite, syenite, 
and limestone, the granular concretions of which they are com- 
posed, are either simply attached or intermixed at their line of 
junction, or branches shoot from the one into the other ; and 
these arrangements, which must be considered as indicating cry- 
stallization from a state of solution, also occur in quartz-rock 
and its sandstone ; and hence these also are to be viewed as 
chemical formations. 
3 . 
Small masses of fine granular granite sometimes occur im- 
bedded in coarse granular varieties, and occasionally masses of 
coarse granular granite are inclosed in fine granular. These 
masses, at their line of junction with the inclosing granite, are 
sometimes distinctly separated, or they are intermixed with it, or 
gradually pass into it, and frequently they send out branches or 
veins in all directions into the surrounding rock. These charac- 
ters prove the chemical and also cotemporaneous formation of 
these masses with the surrounding rock. It frequently happens 
that masses having all the characters of quartz-rock are im- 
bedded in granite, and these, at their line of junction with it, 
present the appearances already described in the inclosed granite 
masses. Similar masses of granite occur in quartz-rock, and 
in sandstone, and sandstone also occurs in quartz-rock and gra^ 
nite ; — facts illustrative of the chemical and cotemporanejirs 
formation of all these rocks. 
4. 
Having shewn that granite, quartz-rock, and red sandstone, 
are chemical formations, and that they are sometim.es of cotem- 
poraneous formation on the small scale, we may next inqume if 
