The course of creation

by John Anderson

The happy seat

Of some new race, called Man.”

The idea here so beautifully expressed is, that the cosmical arrangements of the earth were, from the beginning, so conducted as to be subservient to man’s well-being; and, certainly, nothing could show more the dignity of the new race, or the interest taken in them by their Creator, than this tradition which ran of them in other spheres. But geology, more to be relied on than poetry, furnishes demonstrative evidence of the anterior designs and purposes of Omnipotent Wisdom in actually fitting up “the happy seat,” and in storing it beforehand with materials suited to the wants and comfortable subsistence of him who was to be its loftiest inhabitant. The coal-metals, in the discovery of their history and position, alone vindicate the importance of geology as a science. The whole group with which they are associated, in their mineral and vegetable contents, their place in the system, and the means provided at once for protection and excavation, manifest a series of contrivances so expressive of design, as cannot fail, when read aright, to draw forth our gratitude and wonder.

I. The Mineral Ingredients, Position, and Arrangement of the Carboniferous System.—The rocks belonging to this formation, in the order of superposition, succeed the old red sandstone, consisting of a series of deposits of great thickness, of an infinite number of alternations and varieties, and nearly the same in every coal-field all over the earth. They constitute one great group of marked physical characters, formed under similar conditions, and produced during the same epoch or period of time. The out-crop of the beds meets the eye along the ridge of which the Lomonds may be taken as the center, ranging eastward by St. Andrews to Fifeness Point, and extending indefinitely westward by Stirling, Campsie Hills, Port-Glasgow, to the coast of Arran. The southern lip of the great coal basin of Scotland stretches from the German Ocean, near Dunbar, to the Ayrshire coast in the North Channel, flanked by the old red sandstone and Silurian rocks almost continuously throughout. And within the space now indicated are situated all the principal coal-fields of the northern part of the empire.

The lower beds of the formation consist generally of coarse-grained sandstone, termed by the English geologists millstone grit, and inclose a few thin unworkable seams of coal. Bands of ironstone, shale, and sandstone are superimposed in repeated alternations. A thick massive limestone lines the edges, feathering in and out through the area of the basin which contains the coal metals. This is the mountain limestone, the most of which is supposed to have once existed as coral reefs, raised on the bottom of shallow seas, so subdivided as to form suitable compartments for receiving and retaining the matter of the coal. Accordingly, corals, encrinites, and shells everywhere prevail in the rocks of this deposit, and, in some instances, present the appearance of a homogeneous, agglutinated mass of the remains of these marine animals—the first of living creatures which the waters were charged to bring forth, and with which they were now swarming. The bituminous beds, the true coal, generally occupy a central position in the group, firmly caked and inclosed between the arenaceous and shaly strata. The number of seams vary in different basins, ranging in Scotland from eleven to thirty-two or thirty-three, and comprising an average thickness of the useful mineral of a hundred and twenty feet. The varieties of coal—as anthracite or blind-coal, cannel or parrot, and the common house or glance-coal—are occasioned chiefly by the different proportions of the bituminous elements which enter into their composition. Compared with Scotland, the coal-measures of England and Wales are of a greater average thickness, lie far beneath the surface, and contain in general a greater proportion of bitumen.

The basin containing the coals, as defined above, is inclosed within the great chains of primary and secondary mountains of the central district of Scotland, which were upheaved into dry land before the coal-measures were formed. A period of violent disturbance had thus passed away, when the carboniferous formation bears evident tokens of having been begun and completed in tranquil waters. But after being collected, the coal-metals were exposed to the action of disturbing forces: eruptive masses, of igneous origin, have invaded their domain; basalts and greenstone, trap dykes and veins, are everywhere found within their inclosure; and apparently the utmost disorder and irregularity now reign, where order and stillness once prevailed. But look a little closer: examine the length and breadth of any coal-field in any part of the world, and you will discern proofs of a purpose, not only in the quality of their materials, but in the position, arrangement, and grouping of the metals; those very disturbing forces, to which they and all earthly things have been exposed, giving unequivocal testimony of an overruling intelligence continuing, through all ages, to superintend and guide their various operations.

Study any coal-field in your neighborhood, and observe the place of the mineral. It does not lie exposed upon the surface, but is placed at a considerable depth in the earth; of which many are apt to complain, thinking that, if a different arrangement had prevailed, much needless labor and expense would have been saved. But the constituent elements of coal are such, that by exposure on the surface the mineral would, in a comparatively short period of time, have run to waste and decay. Even a thick covering of earthy mold would not have been sufficient to protect it; and therefore was the treasure purposely hid in the earth, and so inclosed that the floods could not wash it away. Then consider the quality of the rocks by which the coal is protected, and along with which it is invariably associated. These consist of limestone, sandstone, shale, and clay ironstone, which always occupy the same basins, and alternate with the coal sometimes in a series of more than a hundred beds. Such a group of well-characterized rocks not only act as a guide for determining the localities of the valuable mineral, but they serve the double purpose of facilitating the excavation, by affording at once a safe roofing to the mine, and an easy passage for the drainage of the water which accumulates in the pits. No other class of rocks would have been so suitable. The granite and crystalline rocks would have been inconvenient, or wholly unfit: no borings could have been effected through such materials to any extent; the operations underneath would have been equally difficult and unmanageable; and through such hard compact substances the drainage must have been impracticable. But a still more remarkable indication of contrivance arises from the elevated and inclined position into which the coal strata have been thrown. Had they remained in the position which they originally occupied, and been covered with the vast accumulations which have subsequently taken place, their depth would have been utterly beyond the industry of man to have reached. Hence the waters have disappeared, having accomplished the purpose for which they were, in this instance, spread over the earth, and the rocks formed beneath them have lifted up their heads; not uniformly, or in one continuous unbroken mass, but divided into small sections, and inclined in every possible direction. The wisdom of this appears from two considerations: From their inclined position, the various beds of coal are worked with greater facility than if they had been horizontal, a level is produced for the drainage of the water, and the edges of the coal bent upward are brought nearer the surface. But these advantages are, every one of them, increased incalculably by the division of the coal-field into limited sections, whereby less water is allowed to accumulate than if the beds had been indefinitely extended; their lower extremities are prevented from being plunged to a depth that would be inaccessible; and their several portions arranged in a series of tables, like the steps of a stair, rising one behind another, and gradually inclining outward from the lower to the upper seams of the basin. Again, every coal-field is furnished with a system of checks, in the shape of faults or dykes, against floodings, fire-blaze, and other accidents that occur in the operations of mining. These faults or dykes consist of clay, the detritus of the associated rocks, or of intruded whinstone, with which the fractures produced at the period of the disruption and elevation of the coal-field have been filled up, and the various sections of the metal insulated, and contracted to more workable dimensions. They present the appearance of a vertical wall, cutting the strata at right angles; and, though often occasioning much inconvenience and interruption, yet, as every experienced collier well knows, forming upon the whole his greatest safeguard, and essential every way to his operations. To all which add, as constants in every coal-field, the minerals of lime and iron, gifts, both of them, of inestimable value: the former in the amelioration of the soil and construction of every social edifice; the latter ductile and plastic as wax, capable of being welded, and yet, by a slight chemical change, possessed of adamantine hardness; and the coal always there, in juxta-position, to serve as a fuel for the reduction of the limestone and ironstone into their economic properties—properties starting into agency as if by a miracle.

These are a few of the facts connected with the arrangement and distribution of the coal-measures, in whatever quarter of the globe they are found. Is it possible to resist the conclusion, that, in such a disposition of things, there are the clearest indications of contrivance and design? Nay, that the argument derived from the construction and positions of the solid parts of the earth is the same in kind, if not in degree, with that which is so irresistibly demonstrative in the case of the organic structure of the living frame? The dance of atoms imagined by the philosopher of antiquity, could never have terminated in the perfect order and harmony of the heavenly bodies—innumerable systems of worlds maintained,—each hung upon nothing, and duly preserved all of them in their respective spheres. Equally impossible is it to contemplate a disposition of things so adapted, and indeed so indispensable, for availing ourselves of the mineral treasures of the earth—essential to our wants, and ministering so directly to our social comfort and improvement—and yet to refer the whole, or any part, to the blind operation of fortuitous causes. Impossible, indeed, it ever will be, for the human mind to embrace or unravel all the mysteries of creation; but thus admitted to the mighty wonders of the interior, we are almost enabled to trace the history of the moving atoms from their chaotic disorder into their places and arrangement in the visible universe—to see dead matter assuming the forms of life and organization—clothing the earth for a season with luxuriance and beauty—buried for ages under the solid rock—and again, out of coldness and death, affording light, and warmth, and power to the successive generations of men.

II. Origin of the Carboniferous Rocks.—The strata comprised within the coal-measures are variously estimated; being, in some instances, about eleven thousand feet in thickness; in other cases, of much greater depth; and of this mass of matter, the coal itself does not occupy more than a maximum average of one hundred and fifty feet. The shales consist of thin beds of mud, washed down by the rivers from the neighboring heights, and would appear to have formed the soil on which subsisted a rank vegetation; the impressions of plants, roots, and trunks of trees being still found in a standing position. It is from these bands of mudstone that the best specimens of the flora of the period are derived; every thin splitting presenting the most entire and beautifully-preserved figures of fronds and stems. The ironstone is usually mixed up or associated with the shales, and consists, like them, of comparatively thin beds of ferruginous clay. The sandstones, of which the greater proportion of the mass consists, have clearly resulted in the continued action of the same causes that produced the old red deposit of the anterior period. But the two remarkable products of the age are the calcareous and coaly strata, which give character to the system as well as the epoch in which they were formed; the one showing a sudden development of carbonate of lime, and the other an increase of vegetable matter, whose enduring monuments point them out as the most striking cotemporaneous and co-extensive formations on the surface of the globe, or connected with the history of our planet. The bituminous products of the Silurian period, if the anachronism may be pardoned, are but as the gleanings after the full harvest.

The limestone is unquestionably of marine origin, as the countless myriads of testacea inclosed in it testify, and was probably constructed by the primeval families of those island-making architects by which the coral-reefs of our present seas are raised, and whose instincts have found them similar employment in all ages of the world. The limestones of the earlier systems may have been formed in the same manner; and then, as in the subsequent period, we must go to the great original storehouse of Nature for the materials on which they worked. The spoils of the primary rocks could not supply them, as the quantity of the carbonate of lime therein contained bears no proportion to the masses which constitute the mountain limestone group. But the calcareous substance was already, in some elementary form, in combination or otherwise, in existence—the animals capable of secreting and arranging it anew, as the secondary instruments of creation, were abounding in the seas—shallow bottoms over the subjacent sandstones of the devonian system, and within the required conditions of life, were prepared for their operations. The waters had now brought forth abundantly the moving creatures, which, at first more scantily distributed, produced the limestone of the silurian rocks, as the arborial remains of the land, in like stinted measure, are inclosed in the older palæozoic deposits. Their day of increase as it advanced, each after their kind, is recorded in the vast accumulations of animal and vegetable matter which compose the strata of the carboniferous system, both of an order and quality purposely so arranged, and never upon the same scale of magnitude to be repeated in the combustible mineral.