PREFACE. THE author does not profess, in the following pages, to furnish the geological proficient, with descriptions of new forms of mountain rock, or mineral superposition; nor, had he possessed any such store of original observation, would he have deemed this the fitting occasion to display it. His leading object has been to distribute the most interesting and best established truths, illustrative of the structure and revolutions of the earth, in the order of their physical connexions and causes; whence certain general inductions might be legitimately seen to flow. In executing this task he has drawn freely from every authentic source of geological knowledge within his reach-careful merely to quote his authorities, and to acknowledge his obligations; without descending to such minuteness of reference as might savour of pedantry. He has honestly endeavoured to seek the proper end of philosophy, by arranging multifarious and seemingly discordant facts, into a chain of natural links; an object which, if even partially gained, will constitute the chief novelty, and recommendation of his work. There is one treatise, the Geology of England and Wales, by Conybeare and Phillips, to which his debt is so considerable, as to call for preliminary avowal. He has followed in his account of secondary superpositions, the route so ably traced in their " inestimable work,"* under a conviction that this island offers in its geology an epitome * So styled by Dr. Buckland, Geol. Trans. 2d Ser. Vol. II. p. 124. Such also was the sentiment of Dr. Wollaston, that bright star, whose early setting under our horizon, Friendship and Science equally deplore. In one of the familiar interviews with him which rendered my visits to the metropolis so delightful, he pointed to the newly published volume of Conybeare and Phillips lying on his table, saying, "there is a small . book for the price, but it is the cheapest that I know.” of the globe, so that the observer who makes himself familiar with our strata, and the fossil remains which they include, has not only prepared himself for similar inquiries in other quarters, but is already, as it were, acquainted by anticipation with what he must expect to find there.* And he indulges the hope that his volume may prove an introduction and incentive to the study of theirs. The author has likewise diligently availed himself of the ample means accumulated in the Ossemens Fossiles of Baron Cuvier, the Philosophical and Geological Transactions, &c. of enlivening the dark catacombs of the earth, by interspersing among his descriptions of its mineral planes, an account of their ancient tenants. By transferring to his pages, systematic exemplars of the analytical science displayed by the great naturalist of France, in restoring antediluvian zoology, he expects to make them peculiarly attractive to the English reader. In a book intended for general perusal, perhaps an apology may be due for the apparent abstruseness of the chapter on Light. But this was a subject of such vital interest to the proposed line of inquiry, that the author would have deemed himself highly culpable, either to have omitted it altogether, or to have treated it in a more superficial manner. He has spared no pains to simplify the disquisition; and he believes that a moderate mental effort will surmount every obstacle to its comprehension. At any rate, the conclusions are perfectly clear and satisfactory. The liberal spirit of the Publishers has enabled him to enrich the work with a series of illustrations in copper and wood, numerous and costly much beyond the general rule of the trade; advantages for which he is truly grateful. Glasgow, Jan. 26th, 1829. * See Dr. Fitton's eloquent Inaugural Address from the President's Chair, to the Geological Society, Feb. 5th, 1828. INTRODUCTION. THE formation and revolutions of the earth, are subjects of the highest interest to man, and have exercised inquisitive minds in every age. The first philosophy of Greece consisted of physical cosmogony, discussed, however, in a metaphysical manner. Ideal elementary powers and substances were assumed, to which a multitude of phenomena, ill-observed and falsely grouped, were referred. To deduce one efficient cause from the careful collation of analogous effects, was too humble and irksome a process, for the masters of the Ionic, Italian, or Attic schools. Their spirit was essentially dogmatic. Each arrogated supremacy and infallibility to his creed, using every artifice to kindle the zeal of proselytism in the breasts of his disciples. They, unconscious of the falsehood of their master's axioms, and the sophistry of his arguments, propagated the most absurd tenets without reserve. Visionaries of this stamp usurped the rank of philosophers, bringing the very name into contempt. Such were almost all the wranglers who infested Athens, and other celebrated cities of Ancient Greece, under the title of Sophists and Sages. After perverting, with impious speculations, the heads and hearts of their countrymen, they have bequeathed in their imperishable language, a legacy of vain imaginations to every coming age. These dreamers have supplied not only our modern metaphysicians with much of their syllogistic chicane, but they have afforded materials of many geological reveries. How humiliating is it to see the best powers of reason, and the holiest aspirations of the heart, still sacrificed by science falsely so called, to these B heathen phantoms; a century after Newton, and two centuries after Galileo, had laid open the true Temple of Nature, in which man is ordained and qualified to offer a reasonable service! How well this censure of Grecian learning is merited, we may judge from the account given by Brucker, of the philosophy of Leucippus. "The universe which is infinite, is in part a plenum, and in part a vacuum. The plenum contains innumerable corpuscles or atoms of various figures, which falling into the vacuum, struck against each other; and hence arose a variety of curvilinear motions, which continued till at length atoms of similar forms met together, and bodies were produced. The primary atoms being specifically of equal weight, and not being able, on account of their multitude, to move in circles, the smaller rose to the exterior parts of the vacuum, whilst the larger entangling themselves, formed a spherical shell, which revolved about its centre, and which included within it all kinds of bodies. This central mass was gradually increased by a perpetual accession of particles from the surrounding shell, till at last the earth was formed. In the meantime, the spherical shell was continually supplied with new bodies, which, in its revolution, it gathered up from without. Of the particles thus collected in the spherical shell, some in their combination formed humid masses, which, by their circular motion, gradually became dry, and were at length ignited, and became stars. The sun was formed in the same manner in the exterior surface of the shell; and the moon in its interior surface. In this manner the world was formed." According to Epicurus, those atoms which were lightest, mounted up and formed the air, the heavens, and the stars; whilst the more sluggish subsided, and formed the earth on which the human congeries of atoms move about. That men, by uttering such conceits, should gain the reputation of superior wisdom, would hardly be credited, IDOLS AND IDOLATRY OF THE LEARNED. xi did we not meet with modern speculations in Cosmogony no less extravagant, however they be disguised in the scientific language of the day. Our world-framers easily shake off the shackles of inductive logic, and run a fearless career. They will sneer at the pretended infallibility of papal dogmas, and the immutability of papal decrees on the mysteries of faith, but do not scruple to avow doctrines relative to objects of sense, as preposterous as any ever uttered from the Vatican. This persuasion of certainty in his judgments may be somewhat pardonable in the churchman, who believes himself guided by divine inspiration. The student of nature, however, knowing nothing of her attributes, but what he can decipher by vigilant observation of her multiform phases, or by experimental inquiry, should ever preserve the humble docility of a scholar. Like Galileo and Pascal, his only care should be, to arrange in a well ordered series, the record of facts, and collating them by the kindred rules of logic and geometry, to trace out their general results. Into a mind thus disciplined, the spirit of dogmatism can hardly enter. We may rest assured, therefore, that the eager systematist who would heap Ossa on Pelion, to complete his scheme, is no master architect in science. Bacon was the first who clearly showed the danger of cherishing false notions, which became eventually so incorporated with the understanding, as to occupy it exclusively, to the admission or right perception of truth. His denunciation of these idols, as he justly termed them, is perhaps the most valuable part of the novum organum. How dangerous such phantoms may become to man, when associated with the mystery of his being and destiny, the history of all Polytheism attests. When we contemplate idolatry, in the abominable rites of paganism, whether barbarous or civilized, we feel ashamed of our common nature thus debased beneath the level of the brute creation. So shocking indeed is the retrospect to the pride of man, that were the |