Volcanic Rocks. Although there are fortunately no volcanoes to disturb the peace of our country at the present day, there is abundant evidence of their existence in the past. Not only are some of the beds, especially those of Paleozoic age, composed of the dust and ashes thrown out of volcanoes, with here and there a lava flow now hardened into solid rock, but the stumps of the volcanoes themselves are left to tell the tale. The cones indeed are gone, carried off piecemeal by the rain and frosts, and other destructive agencies, in the course of countless ages: not so the once fluid rock within; that cooled down into Granite, and though originally below the surface, it now, owing to the removal of the overlying softer strata, forms raised ground overlooking the surrounding country. The granite masses of Cornwall, of Dartmoor, in the south-west of Mt. Sorrel; the variety called Syenite at Malvern and Charnwood Forest; the Basalts of the Cheviot Hills and of Antrim; the volcanic rocks of Arthur's Seat, Edinburgh, and of the islands of Skye and Mull, etc., are examples of this class of rock. They are of different ages, and belong to different periods of the earth's history, from early Palæozoic down to Miocene times.
TABLE OF THE PRINCIPAL DIVISIONS OF THE ANIMAL KINGDOM,
TO SHOW THE ORDER IN WHICH THE FOSSILS SHOULD BE ARRANGED.
| Invertebrata. | ||
|---|---|---|
| Foraminifera, minute chambered shells like the Nummulite. | ||
| Spongida, Sponges. | ||
| Hydrozoa, Graptolites, etc. | ||
| Actinozoa, Corals. | ||
| Echinodermata, Sea-urchins, Stone-lilies, Starfish, etc. | ||
| Annelida, Worm tracks. | ||
| Crustacea, Trilobites, Crabs, etc. | ||
| Arachnida, Scorpions and Spiders. | ||
| Myriapoda, Centipedes. | ||
| Insecta, Beetles, Butterflies, etc. | ||
| Polyzoa (Bryozoa) or Moss Animals. | ||
| Brachiopods, Lampshells. | ||
| Mollusca | ┐ ├ ┘ | Lamellibranchiata, Bivalves. Gasteropoda, Univalves. Cephalopoda, Cuttlefish, Ammonites. |
| Vertebrata. | ||
| Pisces, Fish. | ||
| Amphibia, Labyrinthodonts, Frogs, and Newts. | ||
| Reptilia, Reptiles. | ||
| Aves, Birds. | ||
| Mammalia, Mammals. | ||
WORKS OF REFERENCE.
FOR NAMING COMMON FOSSILS.
Tabular View of Characteristic British Fossils Stratigraphically Arranged. By J. W. Lowry. Soc. Prom. Christ. Knowledge. 1853.
Figures of the Characteristic British Tertiary Fossils (Chiefly Mollusca) Stratigraphically Arranged. By J. W. Lowry and others. London (Stanford). 1866.
PALÆONTOLOGY.