deposition from the sea, as in the case of Pharos joined to Egypt, and Tyre to Syria, with the analogous instance of Antissa to Lesbos. The formation of islands, by the ocean cutting its way through peninsulas, as Leucadia and Sicily, the latter recognised by tradition as having once been a portion of Italy. The subsidence of land during earthquakes, letting in the sea, or gradually forming lakes, submerging the cities that once occupied those sites, as Buris and Helice in Greece. The upheaving of plains, and the diversions of level ground into mountains, as at Troezene in the Peloponnesus. The displacement and limited duration of volcanic vents. "There was a time," says Ovid, as the exponent of Pythagoras, "when Etna was not a burning mountain; and a time will arrive when it will cease to burn." It must be acknowledged that the philosopher who noted such events as these, had acquired just views of the physical mutations to which our globe is subject, and of the complicated powers that operate in varying its condition. The path marked out in bygone days has been ably followed by Sir C. Lyell; and it scarcely admits of a doubt, that all geological phenomena are the effects of physical forces now in action, however questionable his general proposition respecting the perfect equality of their intensity in ancient and in modern times. The changes wrought by these natural agencies in the sweep of ages, acting with varying vigour, of which any one who has eyes, and will use them, may see the evidence, were never better illustrated than by an Arab fable, beautiful for its simplicity, and striking for its truth. It occurs in a manuscript of the thirteenth century, in the following narrative from an allegorical personage: "I passed one day by a very ancient inhabitants how long it had been founded? and populous city, and I asked one of its It is indeed a mighty city,' replied he; 'we know not how long it has existed; and our ancestors were on this subject as ignorant as ourselves.' Some centuries afterwards, as I passed by the same place, I could not perceive the slightest vestige of the city. I demanded of a peasant, who was gathering herbs upon its former site, how long it had been destroyed? In sooth, a strange question,' replied he; the ground here has never been different from what you now behold it.' Was there not,' said I, 'of old, a splendid city here?' 'Never,' answered he, 'so far as we know ; and never did our fathers speak to us of any such.' "On my return there again, after the lapse of other centuries, I found the sea in the same place, and on its shores were a party of fishermen, of whom I inquired how long the land had been covered by the waters? Is this a question,' said they,' for a man like you? This spot has always been what it is now.' "I again returned ages afterward, and the sea had disappeared. I inquired of a man who stood alone upon the ground, how long ago the change had taken place? and he gave me the same answer that I had received before. "Lastly, on coming back again, after an equal lapse of time, I found there a flourishing city, more populous and more rich in buildings than the city I had seen the first time; and when I would fain have informed myself regarding its origin, the inhabitants answered me,' Its rise is lost in remote antiquity; we are ignorant how long it has existed; and our fathers were on this subject no wiser than ourselves."" With the exception of this myth, which presents us with a graphic picture of the physical history of the earth, there is nothing of interest, in a geological point of view, in the interval between the loss of the ancient civilisation, and the dawn of true inductive science. Dreamers resolved fossil shells and fishes into lusus naturæ, and attributed them to "a plastic virtue latent in the earth," or to " the tumultuous movements of terrestrial exhalations," or to the influence of the heavenly bodies. Scott, in his "Marmion," refers to a legend once prevalent in the neighbourhood of Whitby, that the ammonite shells, which are common in that vicinity, had formerly been snakes, which the foundress of the abbey, St. Hilda, succeeded in decapitating by her prayers, and then converting into stone: "And how the nuns of Whitby told, How of countless snakes, each one Themselves within their sacred bound It was not until the end of the seventeenth century that the animal origin of fossil remains was generally admitted; and the eighteenth was drawing to its close before an extended and enlightened prosecution of geological pursuits commenced. No individual contributed more to enlist votaries in this service than Werner did, by the charm of his eloquence, however unfortunate in the theory he advanced, which referred the formation of all rocks to chemical precipitation from water. Abraham Gottlob Werner was born in the year 1750, at Welslau on the Queiss, in Upper Lausitz, where his father had the superintendence of a foundery. He gave the child minerals for playthings, who thus became acquainted with their names and characters in his tender years, and imbibed that love for mineralogy which distinguished his advanced life. Appointed, in his twenty-fifth year, professor of that science in the School of Mines at Freiberg, and subsequently Chancellor of the mines of Saxony, he devoted himself to mineralogy, and to advance views of the structure of the earth; soon attracting round him, by his captivating mode of lecturing, a number of admiring students, among whom the names of Alexander Humboldt, Von Bûch, D'Aubuisson, Jameson, Englehart, and Emmerling occur. It was maintained, in the Wernerian system, that volcanic action is of recent date, and was inoperative in the early history of the globe; that all rocks-basaltic, trap, and granite-as well as the secondary and tertiary beds-had been produced by a series of depositions formed in succession from water; and hence the followers of Werner took the name of Neptunists, in the controversy which ensued with the disciples of Hutton, who were called Vulcanists, as the advocates of igneous action. Werner proceeded to generalise upon few and insufficient data, taking Saxony as a miniature picture of the earth; though even here many appearances were overlooked or misinterpreted. The fallacy of his doctrine respecting the aqueous origin of all rocks is now universally admitted; but the faults of his system should not blind us to the merits of the man, who was one of the first to recognise the existence of natural groups of strata in a certain order of superposition, and who succeeded in enthusiastically attaching some of the finest minds of the day to geological inquiry-in several instances, to aid in overthrowing the theory of the teacher. A contemporary of the Freiberg professor, in Scotland-Dr. James Hutton-proposed views concerning the formation of the mineral masses, founded upon the phenomena of universal nature, which, though little appreciated in his lifetime, at last completely exploded the theory of the Neptunists, and now rank among well-established geological doctrines. The object of Hutton was not to explain the origin of things, but to elucidate their existing state, by the agency of known causes. The following propositions are the leading features of his system: 1. That a great portion of the crust of the globe is formed out of more ancient materials; that all the stratified rocks consist of the remains of other strata, more ancient than themselves. 2. That the greater part of the present continents, having once existed in a sedimentary state at the bottom of the sea, must have been consolidated by some powerful agent; that this agent is subterraneous heat, which is freed from the objections urged against it, by the principle of compression restraining the volatility of many substances, which cannot exist upon the surface except in the form of gas, and compelling them to remain in combinations impossible under the pressure of the atmosphere alone. 3. That the stratified rocks, instead of having a horizontal position, being actually inclined at various angles, or even vertical,-being inflected, broken, and the portions often detached from each other, beds of the same character occurring at various elevations, and sometimes at the greatest heights above the sea, they have been raised, therefore, by some expansive force acting from beneath, which approximates closely to the cause of the volcano and the earthquake: this force is heat. 4. That veins, whether metalliferous or composed of stony substances, are of posterior formation to the strata which they intersect; that their materials have generally been melted, and ejected from below; and that this condition extends to the masses of whinstone, granite, and other unstratified rocks, which are sometimes interposed among the sedimentary strata, and which have been forced up through or injected among them, heat being the cause of the propulsion. Hutton appears to have arrived at these views by a course of independent investigation, though anticipated in a few points by some Italian writers; and all modern observation has tended, while slightly modifying his principles, to confirm and extend them in the main. There are no geologists of note who do not agree in the following doctrines: that the granitic, trappean, and basaltic masses are the result of simple fusion; that the rocks of igneous origin have been violently injected among the stratified deposits, by an upheaving force, elevating and indurating them, at various epochs; and that this mighty power from within, is the expanding property of internal heat, whatever be its nature or its cause. The igneous theory, during the life of its author, and for some years after his death, encountered general neglect, and, from various quarters, virulent opposition. Some 66 unguarded expressions alarmed the religious world; and the odium of infidelity becoming attached to his name, the current of public opinion set in strongly against his views. On the other hand, Werner had obtained the adherence of the scientific, by his zeal and eloquence; and his system being supposed to be valuable evidence in favour of the diluvian catastrophe in the sacred records, it received the homage of the public mind. The continental geologists especially were steady Wernerians long after the doctrines of Hutton had become the established faith of the English philosophers. Cuvier, in his éloge of De Saussure, read in the year 1810, remarked, that "he overthrew the doctrine of central fire-of a source of heat placed in the interior of the globe," and continued to the last "a believer in the aqueous origin of granite." Eight years afterwards, in 1818, in pronouncing his éloge of Desmarest, Cuvier speaks of a new sect, to which the name of Plutonians had been assigned, because they went so far as to attribute to the action of fire, rocks, even the most universally expanded over the surface of the globe, and which no person till then had ever dreamed of withdrawing from the domain of water!" Again, in the same éloge, alluding to Von Bûch's researches in Auvergne, Cuvier observes, with surprise: "In his enthusiasm, from having been a zealous Neptunian, he became almost Plutonian. It is not basalt alone that he ascribes to volcanic action: porphyry itself, which forms a protuberance of more than sixteen leagues in diameter, of which Mont D'Or is the centre, has been, if not thrown out, uplifted by volcanic power!" It is evident, that down to the period referred to, the illustrious Frenchman was a disciple of the Wernerian school; and this was the case also with most of the continental physical inquirers, when the igneous theory, having emerged from obscurity in England, had conquered opposition, and won the assent of Jameson, Macculloch, Buckland, and Conybeare. In a sketch of the progress of knowledge relative to the economy of the underlying masses which observation can reach, it is impossible to omit the name of William Smith, -commonly, and justly, called the father of English geology,-who, without the furniture of high education, or the advantages of wealth and patronage, conducted a series of laborious examinations of the stratified formations, chiefly in the midland and southern counties of his native country, and arrived at the discovery of a fact, which Sedgwick has styled "the master-principle of our science." Commencing his career as a humble surveyor, his mind soon became impressed with a deep conviction of the regular succession and continuity of strata; and by a minute analysis of them, he grasped the truth, that the organic remains of animal and vegetable life in the earth were definitely distributed. By a course of patient investigation, he reached the sublime conclusion, that each stratum, wherever it occurred, in detached masses, and in distant localities, presented its own peculiar species of fossils, and might be identified by this characteristic mark; so that, exhibiting a particular fossil, it might instantly be declared from what rock, and even bed of stone or clay, the specimen had been derived. The important doctrine was thus established, that there had been a systematic succession of life in the ancient earth; that, during the formation of its stratified crust, different races of animals and plants had appeared and vanished; each stratified rock being thus a kind of museum, preserving specimens of the organic life existing during the period of its deposition. The coming in of new organic forms, and the extinction of those that pre-existed on the earth, realises the sentiment expressed in a line of Ariosto, "Natura il fece, e poi ruppe la stampa," "Nature made it, and then broke the die." Besides developing this important doctrine, "Stratum Smith," as he was familiarly called, took the lead in constructing a geological map of England, which, though superseded by the labours of Mr. Greenough, was worthy of his name, and gave the hint for making those surveys, by the practical illustration of their advantages, which Macculloch, Von Bûch, and others followed in their respective countries. Of this work, D'Aubuisson observed, "that what many celebrated mineralogists had only accomplished for a small part of Germany, during half a century, had been effected by a single individual for the whole of England." Upon the importance and interest of geological investigations becoming more extensively appreciated, societies were organised at home and abroad for the purpose of facilitating such inquiries, whose published transactions are monuments of the admirable energy and strict philosophical spirit with which the object has been pursued; nor is it too much to say, that no individuals, in any age of the world, have established a stronger claim to confidence than the members of the Geological Society of London by their personal labours, to arrive at a just knowledge of facts. It has been the grand maxim of that institute to multiply and record accurate observations, leaving theory in abeyance until sufficient materials for generalisation have been gathered; a principle which has been faithfully kept in view, and which has equally distinguished the researches of the leading geologists of the Continent. To this department of science, many of the arts of life are indebted for their rapid advance in modern times; and its cultivation may justly be regarded as one of the elements of our social prosperity. An improved agriculture has resulted from the knowledge of the nature of soils, and of the due admixture of those ingredients-clay, flint, and lime— which constitute the most fertile and the least exhaustible land; while the operations of draining, and of conducting moisture to dry and friable soils, has been facilitated by an acquaintance with the strata of districts, their disturbances, and lines of dislocation. The civil engineer, who has to construct a railroad or a canal, geology directs in the route to be pursued through those deposits which are workable at the least expense, or whose masonry and mineral contents will yield the best return to the promoters of the enterprise ; and, from the same source, the architect receives valuable aid in the selection of building materials. Oxford and Bath furnish many examples of crumbling edifices, of which also the Capitol at Washington is an instance, having been constructed of a stone that readily yields to the action of the atmosphere; and hence the British senate, in erecting new Houses of Parliament, referred the selection of the material to a commission of geologists, by whom one of the durable magnesian limestones was chosen. Some of the finest works of art have become disfigured or entirely ruined in the lapse of time, in consequence of the ignorant selection, by the sculptor, of stone liable to chip and decompose, or impregnated with the metallic oxides. But it is especially in the conduct of mining operations that geology has displayed its practical utility. A knowledge of the position occupied by the coal or ironstone strata, and of the rocks usually associated with them, has guided the capitalist to the spot where he might engage in the search for these products with the least chance of disappointment; and had the directions of science been sought in many instances, and followed, vast sums would have been saved to the community, that have been expended upon a useless quest. Deceived by appearances, or misled by designing individuals, coal has been sought by public companies at a great expenditure, in the wealden formation of Sussex, the oolites of Oxfordshire and Northamptonshire, and the silurians of Radnorshire; whereas an attention to the simplest principles of geology would have shown the folly of such schemes. Because Pennsylvania is rich in coal, it was imagined in the neighbouring state of New York that the precious gift might be found there also; and the resemblance of certain silurian rocks on the banks of the Hudson river to the bituminous shales of the true coal formation, appeared to sanction the surmise. Accordingly mining adventurers squandered away a large amount of capital in sinking shafts there, below the carboniferous series, until geology, at the invitation of the legislature, authoritatively declared the futility of such attempts. Besides its economical value, geological science possesses a thrilling dramatic interest, which invests it with peculiar fascinations. It unfolds the successive conditions of the |