Tests of relative Age of Volcanic Rocks. — Why ancient and modern Rocks
cannot be identical. — Tests by Superposition and intrusion. — Test by
Alteration of Rocks in Contact. — Test by Organic Remains. — Test of
Age by Mineral Character. — Test by Included Fragments. — Recent and
Post-pliocene volcanic Rocks. — Vesuvius, Auvergne, Puy de Come, and
Puy de Pariou. — Newer Pliocene volcanic Rocks. — Cyclopean Isles,
Etna, Dikes of Palagonia, Madeira. — Older Pliocene volcanic Rocks. —
Italy. — Pliocene Volcanoes of the Eifel. — Trass.