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population, riches, and power, and of improvement in almost every Art which administers to the necessities and comforts of Mankind. And, however remote may have been the periods, at which these materials of future beneficial dispensations were laid up in store, we may fairly assume, that, besides the immediate purposes effected at, or before the time of their deposition in the strata of the Earth, an ulterior prospective view to the future uses of Man, formed part of the design, with which they were, ages ago, disposed in a manner so admirably adapted to the benefit of the Human Race.
Proofs of Design in the Effects of Disturbing Forces on the Strata of the Earth.
In the proofs of the agency of a wise, and powerful, and benevolent Creator, which we have derived from the Animal and Vegetable kingdoms, the evidence has rested chiefly on the prevalence of Adaptations and Contrivances, and of Mechanisms adapted to the production of certain ends, throughout the organic remains of a former world.
An argument of another kind may be founded on the Order, Symmetry, and Constancy, of the Crystalline forms of the unorganized Mineral ingredients of the Earth. But in considering the great geological phenomena which appear in the disposition of the strata, and their various accidents, a third kind of evidence arises from conditions of the earth, which are the result of disturbing forces, that appear to* a certain degree to have acted at random and fortuitously.
chinery, which can be kept in action only by the produce of our native Coal Mines, and whose prosperity can never survive the period of their exhaustion.
Elevations and subsidences, inclinations and contortions,fractures and dislocations, are phenomena, which, although at first sight they present only the appearance of disorder and confusion, yet when fully understood, demonstrate the existence of Order, and Method, and Design, even in the operations of the most turbulent, among the many mighty physical forces which have affected the terraqueous globe.*
Some of the most important results of the action of these forces have been already noticed in our fourth and fifth chapters; and our first Section, PI. 1, illustrates their beneficial effect, in elevating and converting into habitable Lands, strata of various kinds that were formed at the bottom of the ancient Waters; and in diversifying the surface of these lands with Mountains, Plains, and Valleys, of various pro
• "Notwithstanding the appearances of irregularity and confusion in the formation of the crust of our globe, which are presented to the eye in the contemplation of its external features, Geologists have been able in numerous instances to detect, in the arrangement and position of its stratified masses, distinct approximations to geometrical laws. In the phenomena of anticlinal lines, faults, fissures, mineral veins, &c. such laws are easily recognised." Hopkin's Researches in Physical Geology. Trans. Cambridge Phil. Soc. v. 6. part 1.1835.
"It scarcely admits of a doubt," says the author of an able article in the Quarterly Review, (Sept. 1826, p. 537,) "that the agents employed in effecting this most perfect and systematic arrangement have been earthquakes, operating with different degrees of violence, and at various intervals of time during a lapse of ages. The order that now reigns has resulted therefore, from causes which have generally been considered as capable only of defacing and devastating the earth's surface, but which we thus find stronggrounds for suspecting were, in the primeval state of the globe, and perhaps still are, instrumental in its perpetuaL renovation. The effects of these subterranean forces prove that they are governed by general laws, and that these laws have been conceived by consummate wisdom and forethought."
"Sources of apparent derangement in the system appear, when their operation throughout a series of ages is brought into one view, to have produced a great preponderance of good, and to be governed by fixed general laws, condusive, perhaps essential, to the habitable state of tho globe," Ibid. p. 539,
ductive qualities, and variously adapted to the habitation of Man, and the inferior tribes of terrestrial animals.
In our last Chapter we considered the advantages of the disposition of the Carboniferous strata in the form of Basins. It remains to examine the farther advantages that arise from other disturbances of these strata by Faults or Fractures, which are of great importance in facilitating the operations of Coal mines; and to extend our inquiry into the more general effect of similar Dislocations of other strata, in producing convenient receptacles for many valuable Metallic ores, and in regulating the supplies of Water from the interior of the earth, through the medium of Springs.
I have elsewhere observed* that the occurrence of Faults and the Inclined position in which the strata composing the Coal measures are usually laid out, are facts of the highest importance, as connected with the accessibility of their mineral contents. From their inclined position, the thin strata of Coal are worked with greater facility than if they had been horizontal; but as this inclination has a tendency to plunge their lower extremities to a depth that would be inaccessible, a series of Faults;> or Traps, is interposed, by which the component portions of the same formation are arranged in a series of successive tables, or stages, rising one behind another, and elevated continually upwards towards the surface, from their lowest points of depression. (See PI. 65. Fig. 3. and PI. 66. Fig. 2.) A similar effect is often produced by Undulations or contortions of the strata, which give the united advantage of inclined position and of keeping them near the surface. The Basin-shaped structure which so frequently occurs in coal fields, has a tendency to produce the same beneficial consequences. (See PI. 65 Figs. 1. 2. 3.)
But a still more important benefit results from the occurrence of Faults or Fractures,^ without which the contents of many deep and rich mines would have been inaccessible. (See PI. 65. Fig. 3. and PL 66. Fig. 2.) Had the strata of Shale and Grit, that alternate with the Coal, been continuously united without fracture, the quantity of water that would have penetrated from the surrounding country, into any considerable excavations that might be made in the porous grit beds, would have overcome all power of machinery that could profitably be applied to the drainage of a mine; whereas by the simple arrangement of a system of Faults, the water is admitted only in such quantities as are within control. Thus the component strata of a Coal field are divided into insulated masses, or sheets of rock, of irregular form and area, not one of which is continuous in the same plane over any very large district; but each is usually separated from its next adjacent mass, by a dam of clay, impenetrable to water, and filling the fissure produced by the fracture which caused the Fault. (See PI. 66. Fig. 2. and PI. 1. Figs. /,—I, 7.)
* Inaugural Lecture, Oxford, 1819.
t "Faults," says Mr. Conybeare, "consist of fissures traversing the strata, extending often for several miles, and penetrating to a depth, in very few instances ascertained; they are accompanied by a subsidence of the strata on one side of their line, or (which amounts to the same thing) an elevation of them on the other; so that it appears, that the same force which has rent the rocks thus asunder, has caused one side of the fractured mass to rise, or the other to sink.—The fissures are usually filled by clay." Geology of England and Wales, Part I. p. 348.
If we suppose a thick sheet of Ice to be broken into fragments of irregular area, and these fragments again united, after receiving a slight degree of irregular inclination to the plane of the original sheet, the reunited fragments of ice will represent the appearance of the component portions of the broken masses, or sheets of Coal measures we are describing. The intervening portions of more recent Ice, by which they are held together, represent the clay and rubbish that fill the Faults, and form the partition walls that insulate these adjacent portions of strata, which were originally formed, like the sheet of Ice, in one continuous plane. Thus each sheet or inclined table of Coal measures, is enclosed by a system of more or less vertical walls of broken clay, derived from its argillaceous shale beds, at the moment in which the Fracture and Dislocation took place; and hence have resulted those joints and separations, which, though they occasionally interrupt at inconvenient positions, and cut off suddenly the progress of the collier, and often shatter those portions of the strata that are in immediate contact with them, yet are in the main his greatest safeguard, and are indeed essential to his operations.*
The same Faults also, while they prevent the Water from flowing in excessive quantities in situations where it would be detrimental, are at the same time of the greatest service, in converting it to purposes of utility, by creating on the surface a series of Springs along the line of Fault, which often give notice of the Fracture that has taken place beneath. This important effect of Faults on the hydraulic machinery of the globe extends through the stratified rocks of every formation. (See PI . 69. Fig. 2.) It is also pro
* "If a field of coal (says Mr. Buddie) abounding in water, was not intersected with slip Dikes, the working of it might be impracticable, as the whole body of water which it might contain would flow uninterruptedly into any opening which might be made into it; these Faults operate as Coffer Dams, and separate the field of coal into districts."—Letter from Mr. John Buddie, an eminent Engineer and experienced Coal Viewer at Newcastle, to Prof. Buckland, Nov. 30,1831.
In working a coal Pit, the Miner studiously avoids coming near a Fault, knowing that if he should penetrate this natural barrier, the Water from the other side will often burst in, and inundate the works he is conducting on the dry side of it.
A shaft was begun about the year 1825, at Gosforth, near Newcastle, on the wet side of the 90 fathom Dike, and was so inundated with water that it was soon found necessary to abandon it. Another shaft was then begun on the dry side of the dike, only a few yards from the former, and in this they descended nearly 200 fathoms without any impediment from water.
Artificial dams are sometimes made in coal mines to perform the office of the natural barriers which Dikes and Faults supply. A dam of this kind was lately made near Manchester, by Mr. Hulton, to cut off water that descended from the upper region of porous strata, which dipped towards his excavations in a lower region of the same strata, the continuity of which was thus artificially interrupted.