Geological facts; or, the crust of the earth, what it is, and what are its uses

by W. G. Barrett

WOOD PERFORATED RY TEREDINA PERSONATA, LONDON CLAY.

Here let us refer to the septaria, of which we have just spoken; two specimens lie before us, which we will briefly describe. In one (1) the clay is in distinct lozenge-shaped masses of a blue colour, while veins of calcareous spar or crystallized carbonate of lime surround these, which are capable of a beautiful marble-like polish; in the other (2) the clay is of the same colour, only in larger proportions, and the spar is of a deep brown colour, while here and there portions of iron pyrites may be seen; they become beautiful ornaments in a room when cut and polished. It should be added, that the septaria are not without their economic uses, being extensively used as cement after being stamped and burnt.

SEPTARIA

Here we may leave this brief sketch of the Eocene, or lowest beds of the Tertiary. A new creation has been introduced to our view; and although we still wait for the coming of man—the lord and interpreter of all—the contemplation of these successive acts and centres of creation fills our minds with renewed admiration and reverence of Him for whom, and by whom, and to whom are all things. Thus “even Geology, while it has exhumed and revivified long buried worlds, peopled with strange forms in which we can feel little more than a speculative interest, and compared with which the most savage dweller in the wilderness of the modern period—jackal, hyæna, or obscene vulture—is as a cherished pet and bosom friend, has made for us new bonds of connexion between remote regions of the earth as it is, on account of which we owe it a proportionate share of gratitude.”[^[117]]

No. II.—The Miocene.

We shall briefly pass over this period. At Bordeaux, Piedmont, and in Lisbon, this formation is seen; as well as in various other parts of the Continent of Europe. The supposition of Geology is, that during this period “whole regions of volcanoes burst forth, whose lofty but now tranquil cones can be seen in Catalonia, in Spain, in France, Switzerland, Asia, and in America. The Alps, the Carpathian Mountains, and other lofty ranges were at this period partially upheaved. The researches of Sir Robert Murchison have established this fact, by his finding deep beds of limestone, characteristic of the Tertiary period, on the summit of one of the loftiest of the Alps, fully ten thousand feet above the level of the sea.”

No. III.—The Pliocene Period.

This term has already been explained. We shall only detain the reader by a few words respecting the organic remains that characterize this formation. In England it is confined to the eastern part of the county of Suffolk, where it is called “Crag.” This is a mere provincial name, given particularly to those masses of shelly sand which are used to fertilize lands deficient in calcareous matter. The geological name given to this strata is the “Red or Coralline Crag;” and it is so called on account of the deep ferruginous colour its fossils have through extensive oxidization of iron. We give drawings of the fossils of the Red Crag, obtained from the neighbourhood of Ipswich.