General Aspect of Plutonic Rocks. — Granite and its Varieties. —
Decomposing into Spherical Masses. — Rude columnar Structure. — Graphic
Granite. — Mutual Penetration of Crystals of Quartz and Feldspar. —
Glass Cavities in Quartz of Granite. — Porphyritic, talcose, and
syenitic Granite. — Schorlrock and Eurite. — Syenite. — Connection of
the Granites and Syenites with the Volcanic Rocks. — Analogy in
Composition of Trachyte and Granite. — Granite Veins in Glen Tilt, Cape
of Good Hope, and Cornwall. — Metalliferous Veins in Strata near their
Junction with Granite. — Quartz Veins. — Exposure of Plutonic Rocks at
the surface due to Denudation.