fusion; not such as belong to the products of fancy and the visions of possibility, but to the forms of reality and the objects of the senses.

One of the first observations which were made after the distinction of rocky masses in reference to their component parts, was the invariable order of relative position which the different species maintain with respect to each other. Different rocks are seen piled upon one another in mountain ranges; and in digging into the depths of the earth a perpetual and varying succession of strata is discovered. But no change of place is ever found between the upper and lower orders of the series. The lines of junction of the different species, and the strata into which they are individually divided, are parallel to one another. From hence the conclusion is striking; first, that their component parts must formerly have been in a state of fluidity; and, secondly, that the lower rocks in position must have been the first in formation. Their division, therefore, into two grand classes, distinguished no less by their relative position than by the obvious characters of their composition, is highly scientific. A crystalline texture, and the absence of extraneous fossils, mark the series which is lowest in position, and justify the name of primordial; while the earthy composition of the higher series, and the different bodies which they envelop, from fragments of the preceding class to remains of organized bodies, authorize no less for these the appellation of secondary. Both these divisions of rocks are traversed by fissures which are filled with matters wholly foreign to their constitution. These veins are allowed by all to be of posterior formation to the masses between which they are interposed. Sometimes veins of different substances cut through each other, and in this case it is obvious that the one which is cut must have been of older formation than the one which traverses it. The disorder and various degrees of inclination of the planes of the strata point to some great revolution which must have broken their surfaces by the elevation of the upper, or the depression of the lower ridge. Geologists all agree in this unavoidable inference, though they differ from each other as to the nature of the

cause.

The existence of marine exuviæ upon the summits of many of the highest mountains is a fact of the utmost interest; as thence arises the uncontroverted conclusion, that at some former period the ocean had covered their lofty pinnacles, which have subsequently been exposed by the reflux of its waters, or by their gradual elevation above its level.

Thus far do all systems of geology agree, and such are the observations which have formed the basis of their several theories.

Two rival systems have of late divided the attention of geologists, both of which profess to appeal to facts as the foundation of their deductions.

One of these, finding the catises which are at present in action upon the surface of the globe sufficient for the operation of all the changes which are visibly stamped upon its form, compensates the imbecility of these ordinary means by an arbitrary extension of time, and carries back the commencement of their operation to millions of ages; or, rather, it supposes an indefinite power of renovation, which scorus the idea of a beginning, as it precludes the expectation of an end. According to this hypothesis, the continents of the present world have been formed from the detritus of pre-existing lands; the causes which destroyed the preceding mass are now in full action upon the present, and the slow disintegration of rocks by weather and storms, and the gradual abrasion of their surfaces by water, are preparing the birth of new lands, as they ensure the destruction of the old. The hollows of the valleys have been worn to their present depths by the action of the rivers, which originally ran at the level of the highest mountains, and the incessant attacks of the ocean perpetually encroach upon the barriers of the earth, the materials of which it washes away and buries in the depths of its waters. But these depths are the grand laboratory where new combinations are forming from the fragments of a former world, which, being deposited in quiet succession, are modified by the action of an internal fire, which, having melted the lower deposits by the help of the compression of the incumbent weight of waters, will finally raise its new creation into light by its expansive powers. The same causes are again to act upon this new earth, the waters of the atmosphere are again to commence their course from the summits of the mountains, and the sea attacking its new barrier with undiminished force will again precipitate its spoils into the furnaces of the deep.

Such is the geological theory of Dr. Hutton. Its chief sup port has been derived from the ingenious illustrations of Professor Playfair. Under his auspices the igneous origin of the present order of things, and the doctrine of their incalculable and unimaginable antiquity, have derived an importance which has saved them from the merited oblivion which involves many other speculations at least as worthy of being preserved.

The writings of the disciples of the rival school most triumphantly point out the absurdities of the Plutonian theory. Although it is impossible to deny the traces of the agency of fire upon the surface of our planet, proofs of which are even now visible in the dreadful effects of volcanoes and earthquakes, yet the facts relied

upon to shew the universality of this agent are completely disproved. The experimental form which the idea seemed to assume from the well conducted experiments of Sir James Hall, vanishes before the very data necessary to their success. The pressure of a resisting solid may prevent the escape of carbonic acid gas when limestone is acted upon by heat, but it would necessarily permeate every part of an incumbent fluid, and escape unchanged. Moreover, the now established stratification of granite, and the proofs of the newer construction of granite veins, which run into upper formations, are destructive of another of its essential arguments. But had not this been the case, we must confess that we are such old fashioned folks, and so bigoted to certain superstitions which we have imbibed in our youth, that the incompatibility of Dr. Hutton's hypothesis with our faith in the sacred volume would have been alone conclusive against his arguments, and we should have still been content to have remained in unphilosophical ignorance of the solution of an intricate problem, rather than adopt conclusions so glaringly inconsistent with the concurrent testimony of recorded facts and traditional history.

The theory of Werner not only boasts the best connected series of facts for its illustration, but the greatest number of able supporters. The talents and sagacity of the founder himself are of the first class; and it will ever be matter of regret that no account of his labours from his own pen enrich the records of science. Professor Jameson has ably filled the place of expositor and annotator; but it is to the labours of the indefatigable De Luc that we are chiefly indebted not only for illustrations but judicious modifications. This acute philosopher has spent the greater part of a long life in geological pursuits; and the volumes of his travels, with the theoretical application of his observations to the support of the Wernerian, and the refutation of the Huttonian hypotheses, are monuments of logical exactness, and of unwearied assiduity of research.

This theory sets out with a distinction between the effects of causes obviously now in operation, and of others which have ceased to act. Carried back to the formation of granite as the first discernible effect which can be traced, it supposes that all the elements of the globe were held together in one chaotic mass. This mass became fluid by the extrication of the matter of heat, whereby the reciprocal power of the affinities of the different substances was brought into action. The granite strata were the first deposits from this disordered fluid, and the rest of the primitive rocks in the order of their succession. While this operation was in progress, the new-formed strata were fractured

by the power of the expansive fluids which were produced by the different actions of affinity, and sinking into the caverns which were thus formed beneath them, rested in an inclined position. Other formations were again deposited upon these from the remaining fluid, influenced possibly by new affinities brought into action by the extrication of the gaseous matters. Such catastrophes occurred at different intervals, fracturing the rocks by the violence of the commotion. Their fragments were rounded by the tumultuous action of the waters, and gave birth to those immense deposits of water-worn stones which are so often met with in the newer formations. The organic remains which occur in these latter testify the different periods at which the earth was clothed with vegetation, and furnished with its various kinds of animated beings.

There is something more than beautiful in the correspondence of this explanation of the appearances of nature with the inspired account of the creation of the world by the great historian of the Jews. In the emphatic command of "Let there be light," we indistinctly trace a part of that comprehensive design which embraced at once all the beneficial consequences of its fulfilment

The

"There was light:" heat the concomitant, and possibly only a modification of light, loosed at once the bands of nature. spirit of God, indeed, moved upon the face of the waters; the powers of affinity, which we are never tired of admiring in our closets in a small scale, were let loose in the great deep, and dry land appeared, the product of the new combinations. But further still, in the relics of a former world, preserved to us in the bosoms of the rocks, we may trace the order and succession of the creation of organic forms, as recorded in the same history. The older classes of secondary rocks contain remnants of vegetable forms alone; a second and a newer division are rich in the remains of all that the waters brought forth abundantly, while the skeletons and impressions of cattle, creeping things, and beasts of the earth, are discovered only in the newest alluvial formations.

The succession of catastrophes which dislocated the strata in the striking manner which we now trace, wherever their sections are exposed to view, was closed by that last subsidence which brought the waters of the ocean upon the habitations of men. The fountains of the deep were opened, the bed of the sea was changed, and our present continents rose above the retiring flood.

It is not the least ingenious and interesting part of the theory which we are contemplating, that it helps us to infer from the effects of causes which are now in action, and which commenced their course from the period of the last catastrophe of the sur

face of the earth, the time which has elapsed from that period; The bold outline of the boundaries of the sea is in most places broken down by the perpetual agitation of the waves. After every storm fragments of the broken strata fall down upon the gradually accumulating beach, and being rounded by the action of the water, are deposited in heaps at the feet of the rocky cliffs. These heaps increase gradually, and modifying the action of the waves, repel their attacks, and in the lapse of time become covered with the earthy deposits of the land waters, and overspread with vegetation. Thus a kind of chronometer is formed, which with little observation and calculation will give us the probable length of time since first the waves began to act upon the rugged outline of the rock.

The accumulation of sand upon different coasts, the gradually increasing deposits of mud at the mouths of rivers, the progress of new lands, the filling up of lakes, and the raising of marshes by the slow depositions of the sediments of water, together with the formation of stalactitical incrustations, are similar measures of the like period. All these concurrent testimonies prove that the time from the formation of our present continents cannot have exceeded a very few thousand years, affording another proof of the authenticity of that history which relates the stupendous story of the universal deluge,

Such is the outline of the Wernerian theory. It must be allowed to be consistent with the known laws of chemical and mechanical philosophy; and although in many instances it may be thought to have ventured too far into the regions of fancy, yet its speculations have imported from thence no arts to disguise inconsistency, or arms to assist presumption.

Geology within this year or two has assumed a different mien. Observation has superseded useless speculation, and the classification of the different formations of the earth's surface, the distinction and description of different individuals of a series, the analysis of minerals, and the investigation of their properties, have taken the place of useless cavils about remoter causes. It is by such gradual means that we may hope to penetrate the secrets of time; step by step to unravel the long series of past events;to harmonize philosophy with divinity.

In adverting to this revolution in the science we have been con sidering, we are happy in an opportunity of directing attention to the exertions of a body of scientific men, who have lately formed themselves into a society in this country for the advancement of geology, Attached to no particular system, they meet together for the purpose of encouraging and facilitating inquiry, and by the discussion of opinions to elicit truth. Their early