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the great source of perplexity. Until the precise import of the term stratification, for example, be settled and understood, the positive assertion of one observer will be met by the positive contradiction of another: the combatants will continue to waste their strength in air, and the truth will only be made more inextricable by their contention. The more general term disposition, may, perhaps, be sometimes employed with less risk of ambiguity; and the definitions which some of the French writers have given of couche, lit, banc, &c. may, probably, suggest some useful distinctions. While, on the whole, we cordially concur in the general spirit, and in the style of reasoning manifested in this important Essay, we may be permitted to express a desire, that a few of the arguments which are so formally enounced, had been somewhat more fully developed.

ESSAY II. is on the Figure of the Earth. On the supposition that the earth's surface was originally more or less fluid, the result of rotation on its axis would be such a figure as the observations of philosophers have proved that it actually possesses, namely, a spheroid flattened at the poles. Hence a strong presumptive argument in favour of the original fluidity of its superficial materialsan argument which is powerfully confirmed by an examination of those materials, which bear evident marks of having once existed in a soft or fluid state, and most of them in aqueous solution or suspension. The quantity of water requisite for such a condition of things, and its subsequent disappearance, may be points of difficult explanation; but how few of the phenomena of nature are we capable of explaining in a satisfactory manner? The Huttonians, indeed, profess not to go back to the original state of our planet, and, therefore, dispense with a former prevalence of waters; but then they are more pressed with difficulties than other theorists, when they labour to deduce the present figure of the earth from the constant tear and wear of its surface, and from the production of new lands, elevated, at indefinite periods, from the bottom of the seatwo causes which, it should seem, would balance each other, and, consequently, produce no effect.

In regard to the actual figure of the earth, or the inequalities on its surface, Mr. Greenough first endeavours to show its proximate, and, afterwards, its more remote causes,-keeping, however, out of view the changes produced by volcanoes, coral reefs, drifting of sands, and calcareous concretions, as he perfectly acquiesces in Cuvier's account of these partial irregularities. From a very copious induction, he arrives at the general conclusion, that the interstices between mountains and hills have been produced, for the most part, by the removal of matter which previously occupied them. Advancing a step farther, he demonstrates the inadequacy of our present seas and rivers to effect the excavation of extensive

valleys, whence he is led to infer the operation of a deluge, or vio lent rush of waters, which has swept over every part of the globe. The consideration of these positions necessarily involves that of the agreement of strata and rocks, on opposite sides of valleys, rivers, and channels of the sea, as well as the transference of masses of granite to the detached and problematical spots on which they are now found and both these topics are discussed with ability and candour. Another argument is deduced from the nature of bowlder-stones, and alluvial deposits, which, every where, indicate the traces of running water, and seem to have proceeded from the breaking up of rocks at a higher level than themselves. It has likewise been observed, that the larger masses of these substances are generally found nearest to the parent rock; and that those blocks, or pebbles, which are more distant from their native place, are composed of the hardest and most indestructible materials. It is added, that 'Substances which break into cubic or hexagonal 'blocks, are found at a greater distance from their native place 'than those which break into blocks, the angles of which are acute.' The enumeration of granite bowlders in various quarters of the world, evinces the futility of the theory which slides them into the north of Germany on the ice. ***

ESSAY III. On the Inequalities which existed on the Surface of the Earth previously to diluvian action, and on the Causes of these Inequalities.-After admitting, that irregular crystallization, partial deposition, subsidence, earthquakes and volcanoes, may have had considerable influence in producing some of the inequalities on the earth's surface, the author is still disposed to attribute by far the greater number of them to the action of running water. The general occurrence of conglomerate and gray-wacke on the confines of primitive rocks, seems to indicate a deluge similar in kind, though, perhaps, not equal in extent, to that which determined the present outline of the earth. These considerations, which are despatched with much brevity, might, perhaps, with more propriety, have been included in the preceding Essay.

ESSAYS IV. & V. On Formations.-On the Order of Succession in Rocks.-In opposition to the popular Wernerian notions of formations, or series of rocks of alleged contemporaneous origin, the author contends, that neither the intermixture of their ingredients, nor their alternations of occurrence, sufficiently justifies the inference of the simultaneous production of mineral substances; for, rocks generally held to be of very different ages, often present intermixtures of their component parts, or pass into one another, while such a mutual blending is frequently not discoverable in others that are reputed to be of the same age. Yet, when two substances are distinctly incorporated in the same mass, it is difficult to conceive of them as generated at different epochs. Examples

are also cited of alternating substances which are not regarded as coeval, while those which are deemed coeval, do not always alternate. So many exceptions to the principle of universal and partial formations, are, moreover, adduced, and so many formidable difficulties stated against its probability, that it ought, in fairness, to be abandoned.

With regard to the Order of Succession in rocks, too, the facts which the author brings forth from his ample stores, are calculated to shake our faith in the commonly received notions of the Wernerian school. Even the precedence of genealogy assigned to granite has been successfully controverted; for this rock has been found to alternate with gneiss, with mica-slate, and with schistus; nay, killas has been observed passing into it, and dipping beneath it. In some cases, it rests on quartz, on hornstone, on slate; and, in France, not unfrequently, on limestone. Again, the term fundamental has, it should seem, been gratuitously predicated of a particular description of granite; for, by the terms of the proposition, the bottom of this formation has never been seen, and con'sequently we have no means of ascertaining whether it be funda'mental or not.' The tables of sections in Ebel's work may suffice to convince us, that equal uncertainty prevails with respect to the relative position of other rocks reputed primitive. Besides, in almost every country, we find what are termed transition rocks in the midst of primitive districts, or vice versâ ; while the line of demarcation between even the primary and secondary classes, is far less distinct than has been generally supposed.

'It is said in the Wernerian theory, that, after the formation of 'all other strata, an immense deluge suddenly occurred, and as 'suddenly retired, leaving, behind it, those scattered hummocks of 'flötz-trap, which have, for some years, so greatly engaged the at'tention of geologists. The proofs of this catastrophe, we are in'formed, are to be found in the great elevation which these rocks 'occasionally attain; in their broken stratification; in their un'conformable posture; and in the nature of their materials.

'But are trap-rocks really more elevated than others? or their 'stratification more broken? It is time enough to consider infer'ences when we have established facts.-If the posture of trap is ' often unconformable, so is that of granite, sienite, hornblend rock, 'porphyry, primitive greenstone, &c.

'Every rock without exception lies, sometimes, in a conforma'ble, sometimes in an unconformable posture: and perhaps the dif'ferent members of the flötz-trap formation, as often exhibit a want ' of conformity towards each other, as, towards the beds on which 'they repose.-As to the nature of its materials-many of them are 'precisely the same as those found in other formations. The only 'rocks which are cited as peculiar to, and characteristic of, the VOL. I.

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'newest flötz-trap, are basalt, wacké, graystone, porphyry-slate, 'and trap-tuff. I am not sure that I know what graystone is; the 'only locality given of it by Jameson, is Vesuvius, where it is said 'to form a portion of the unchanged rocks. The doctrine, that it 'belongs to the flötz-trap, therefore, is founded on an assumption, 'that we have the means of distinguishing, in volcanic countries, 'substances which have been changed by the volcano from those 'which have not-an assumption somewhat gratuitous. The re'maining substances, viz. basalt, wacké, porphyry-slate, and trap'tuff, are certainly not peculiar to this formation; as in England, Scotland, and Ireland, they are often found interstratified with 'other formations much older."

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ESSAY VI. & VII. On the Properties of Rocks, as connected with their respective Ages.-On the History of Strata, as deduced from their Fossil Contents.-The properties of rocks which are here considered, are their ingredients, structure, specific gravity, consolidation, stratification, posture with regard to the horizon, relative posture to one another, dip and direction, altitude, contained metals, and fossils. On each of these heads the author offers some pertinent remarks; but which our limits will not permit us to particularize. It is of importance, however, to notice, that the supposed relation between the age of a rock and the fossils which it contains, is often fallacious; and that the various facts which have now been collected concerning the interesting phenomena of organic relics, demonstrate the inaccuracy of some of the opinions which have been adopted by geologists of the first reputation.

ESSAY VIII. On Mineral Veins.-According to our author's views, fissures have been produced principally by shrinkage; but others may have been caused, or enlarged, by the contraction of an adjoining mass, by the shock of an earthquake, or by failure of support, the erosion of subterranean waters occasioning subsidence. These fissures, or chasms, when filled with mineral matter, are called veins. Mr. Greenough makes some excellent observations on their varieties, anomalies, and probable indications, which cannot fail to interest both the speculative geologist and the practical miner: but, while he rejects both the Huttonian and Wernerian hypotheses, relative to their formation, he sheds little original light on this obscure subject.

On the whole, however, he possesses the rare merit of stating his facts and opinions in a clear and manly, yet modest and respectful manner, untrammelled by preconceived systems, and unseduced by the fascination of great names. Truth, and truth alone, appears to have been the object of his extensive travels, of years of unwearied study, and of the devotion of an ample fortune to the prosecution of his favourite investigations. Nor will such praiseworthy efforts be without their reward, since they must evidently tend to assuage

the angry contentions of conflicting geologists, and to demonstrate the superior value of patient inquiry and research, over hasty generalizations, or the construction of assailable theories. The brevity of the work, too, is the more meritorious, when we consider not only the rarity of that quality in books of this description, but the vast, and, we believe we might say, unparalleled extent both of reading and research which have gone to its composition. The prodigious number and bulk of the publications on Mineralogy and Geology which have been given to the world within these thirty years, have not only put correct information beyond the reach of ordinary readers-but have made it difficult for geologists themselves, at once to extend their own observations, and to keep clearly in view all that has been done by their associates. The work before us not only contains an admirable digest and collation of the most authoritative statements and opinions on a great variety of important questions, but is eminently calculated, by the contradictions which it every where exhibits, to abate the confidence of narrow observers and rash theorists; and to inculcate the necessity of that patient industry and modest skepticism, by which alone the pursuits of Geology can ever attain to the dignity of a Science.

[From the Edinburgh Review, Jan. 1820.]

ART. II. Œuvres Completes de Demosthene et d' Eschine, en Grec et en Français. Traduction de L'Abbé AUGER, de l'Academie des Inscriptions et Belles Lettres de Paris. Nouvelle Edition, Revue et corrigée par J. PLANCHE, Professeur de Retorique au Collége Royal de Bourbon. Paris. Année, 1819,

WITHOUT any ostentation of profound reflection or philosophical remark-with few attempts at generalization-without the glare and attraction of prominent ornaments-with extremely few, and those not very successful instances of the tender and pathetic -with a considerable degree of coarseness, and what we should call vulgarity, particularly in his great oration-and, absolutely, without any pretension to wit or humour, to have acquired the reputation of the Greatest Orator whom the world has ever produced, is a peculiarity which belongs to the character of Demosthenes. In no other instance, in the whole range and circle of the Fine Arts, is the same ascendency admitted, with the same degree of unanimity. Of the three Poets,' for instance, in three distant ages born,' what critic has ever pretended, with any success at least, to class and place them in their due rank and order of merit? Is it not notorious, that with one reader, the vigour and freshness of the father of poetry have superior charms; with another, the de

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