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sufficient quantity to yield a profit, beyond the expense of the process; but we have some other metals, highly useful in the arts, such as zinc, antimony, and manganese.

Besides the substances above mentioned, we have many other mineral treasures of great importance still to be noticed. Of these the most valuable perhaps is limestone, from its use in agriculture, to meliorate the soil and increase its fertility, and from its being an indispensable ingredient in mortar for building; and there are not many parts of the island far distant from a supply of this material. Building stone is found in most parts of the country; and although we must go to Italy for the material for the art of sculpture to be em-* ployed upon, we have free-stones applicable to all the purposes of ornamental architecture, and we have many marbles of great beauty. If stones be far off, clay is never wanting to supply a substitute ; and the most distant nations have their daily food served up in vessels, the materials of which, dug from our clay-pits, have given occupation to thousands of our industrious population, in our potteries and china manufactures. For our supply of salt, that essential part of the daily sustenance of almost every human being, we are not dependent on the brine which encircles our island; for we have, in the mines and salt-springs of Cheshire and Worcestershire, almost inexhaustible stores of the purest quality, unmixed with those earthy and other ingredients, which must be separated by an expensive process, before a culinary salt can be obtained from the water of

the sea.

Familiar as is almost every one of the mineral substances we have named, in the common business of life, there are many persons who have but a very imperfect idea whence they are derived, and what previous processes they undergo, before they can be made applicable to our use.

In the formation of organized bodies, that is, in the structure of animals and plants, the most superficial observer cannot fail to discover a beautiful and refined mechanism; but if we cast our eyes upon the ground, and look at heaps of gravel, sand, clay, and

stone, it seems as if chance only had brought them together, and that neither symmetry nor order can be dis. covered in their nature. But a closer examination soon convinces us of that, which reasoning from the wisdom and design manifested by other parts of creation, we might beforehand have very naturally been led to expect, viz. that in all the varieties of form, and structure, and change, which the study of the mineral kingdom displays, laws, as fixed and immutable prevail, as in the most complicated mechanism of the human frame, or in the motions of the heavenly bodies: and if astronomy has discovered how beautifully “the heavens declare the glory of God," as certainly do we feel assured by the investigations of geology, that the earth “showeth his handy work."--Penny Magazine.


The land rises from the surface of the sea in the forin of islands, and of great continuous masses called continents, without any regularity of outline, either where it comes in contact with the water, or in vertical eleva. tion, its surface being diversified by plains, valleys, hills, and mountains, which sometimes rise to the height of twenty-six thousand feet above the level of the sea. Numerous soundings in different parts of the world have shown, that the bottom of the ocean is as diversified by inequalities as the surface of the land ; a great part of it is unfathomable to us, and the islands and continents, which rise above its surface, are the summits of mountains, the intervening valleys lying in the deepest abysses.

Different climates produce different races of animals, and different families of plants; but the mineral kingdom, as far as the nature of stone is concerned, is independent of the influence of climate, the same rocks being found in the polar and in the equatorial regions.

Although there is considerable diversity in the structure of the earth, it is not in any degree connected with particular zones, as far as relates to circumstances, which are external to it; nor can we say, that the wonderful action which burning mountains tell us is going on in its interior, is confined to any part of the sphere, for the volcanic tires of Iceland burn as fiercely as those that burst forth under the line. From all the observations hitherto made, there is no reason to suppose, that any unexplored country contains mineral bodies, with which we are not already acquainted ; and although we cannot say beforehand of what rocks an unexamined land is likely to be composed, it is extremely improbable, that any extensive series of rocks should be found, constituting a class different from any which have been already met with in other parts of the globe.

When we dig through the vegetable soil, we usually come to clay, sand, or gravel, or to a mixture of these unconsolidated materials; and, in some countries, we shall probably find nothing else, at the greatest depths to which we are able to penetrate. But in most places, after getting through the clay and gravel, we should come upon a hard stone, lying in layers or beds parallel to each other, either of one kind, or of different kinds, according to the depth. This stone would vary in different countries, and in different places in the same country, as well in its constituent parts, as in the thickness, alternation, and position of its beds or layers. It has been ascertained by the observations of geologists, in various parts of the world, that the crust of the earth is composed of a series of such layers, distinguishable from each other by very marked characters in their internal structure. The elements, of which they are composed, are not very numerous, being for the most part the hard substance called quartz by mineralogists, of which gun-flints may be cited as a familiar example, these being wholly composed of it, and the well-known substances, clay and limestone; but these elements are ággregated or mixed up together in so many proportions and forms, as to produce a considerable variety of

rocks. Besides this elementary composition, or what may be termed their simple structure, the greatest proportion of the rocks, that are so arranged in layers, contain foreign bodies, such as fragments of other rocks, shells, bones of land and amphibious animals, and of fishes, and portions of trees and plants. It has further been found, that these different layers or strata lie upon each other in a certain determinate order, which is never, in any degree, inverted. Suppose the series of strata to be represented by the letters of the alphabet, A being the stratum nearest the surface, and Z the lowest: A is never found below Z, nor under any other of the intervening letters ; nor is Z ever found above any of the letters that stand before it in the alphabet: and so it is with all the strata represented by the other letters. It must not, however, be imagined, although this regularity in the order of superposition exists, that all the different members of the series always occur together; on the contrary, there is no instance where they have all been found in one place. It possibly may happen, that where C is found in a horizontal position, by going deeper all the rest would follow in succession; but this we can never know, as the thickness would be infinitely beyond our means of penetrating: and there are reasons, which render the existence of such an un. interrupted series extremely improbable. It very seldont happens, that more than three or four members of the series can be seen together ;-we say of the series, because each member is composed of an almost infinite number of subordinate layers. This order of succession, established by geologists, has been determined by the combination of many observations made in different countries at distant points. The order of three or four members was ascertained in one place; the upper stratum in that place was found to be the lowest member of a second series in another place, and the lowest stratum at the first station was observed to be the uppermost at a third point; and, in like manner, the order of superposition was discovered throughout the whole range. Neither is it to be supposed that the strata, which lie next each other, are always ; $o in

nature; as, for instance, that, wherever G is found associated with another member, it is always, either with F above it, or H below it: it very often happens that F lies upon H, G being altogether absent; and C may even be seen lying on R, the whole of the intervening members of the series being wanting. Very frequently one of the lowest members of the series appears at the surface. Every one may have seen sometimes chalk, sometimes slate, lying immediately beneath the vegetable soil, or even at the surface without that scanty. covering. But if a lower member of the series be seen at the surface, however deep we might go, we should never find any one of those rocks, that belong to the higher members of that series. The immense practical advantage of this knowledge of the determined order of succession will be seen at once ; for if () were found to occupy the surface of the country, it would be at once known, that all search for coal in that spot would be fruitless.



The means, by which geologists have been enabled to fix the order of superposition in the strata composing the crust of the globe, have been partly the mineral composition of each member of the series, partly their containing fragments of other rocks, but chiefy the remains of animals and plants, that are imbedded in them. They observed, that there was a class of rocks distinguished by a considerable degree of hardness, by closeness of texture, by their arrangement in slaty beds, and by possessing, when in thick masses, a glistening structure, called by mineralogists crystalline, of which statuary marble or loaf sugar may be quoted as familiar examples ; and these were, even when associated with rocks of another sort, always lowest.-Above, and in contact with them, another group of strata was ob

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