translation of Playfair's Illustrations' appears, somewhat unaccountably, to have been very little noticed by the French geologists. The fact, however, is certain, that the name of Hutton is never mentioned in M. Brongniart's book.

The interval, in point of date, between the publication of Hutton's Theory' in 1795, and that of M. Brongniart's work, is four-and-thirty years; or, if the date of the more general diffusion of the theory, in 1802, by Mr Playfair's Illustrations,' be preferred, the difference is twenty-seven years; and the latter year, 1802, is still six years before the publication of M. Von Buch's 'Observations on Auvergne,' the earliest of his productions that we are acquainted with, in which theoretic views are particularly treated of.

The opinions of M. VON HUMBOLDT may fairly be taken from his Gisement des Rochers, first published separately, we believe, in 1823; and we shall at present only remark, that the arrangement is certainly not founded on the Plutonic theory. The value of the author's observations, especially in what relates to the transition series, appears, in fact, to be materially diminished by his adhering too closely to the principle of superposition, and not having more fully adopted the Huttonian views respecting the forcible interjection of Plutonic masses among the strata.

We know not, but from conjecture, how far either M. Von Buch or M. Von Humboldt is acquainted with the productions of Hutton or of Playfair; but of this we are perfectly convinced that if the present pages should be so fortunate as to meet the eyes of either of those eminent men, and if our estimate of the value of Hutton's labours be thought by them satisfactory, they will be among the first to acknowledge that they had been anticipated, and will assign to that philosopher whatever justice requires. The sole question, therefore, is how far these authors may have arrived at the same views by independent enquiry, without any acquaintance with Hutton's previous labours?-a point which it is unnecessary to enter upon, since the only acknowledged standard of priority in the history of scientific discovery, must be, from the nature of things, the relative date of well-authenticated publication.

To the works of M. Keferstein, we are not at this moment enabled to refer; but the greater number of M. Boué's publications, to which so prominent a share in the development of the Plutonic doctrine has been assigned by Brongniart, are now before us..

The earliest of these, a Geological Essay on Scotland, was printed at Paris about 1818.* In the dedication to Professor

* Essai Géologique sur l'Ecosse ; par A. Boué. Paris, (sans date.)

Jameson, the author gratefully mentions the years during which he had studied as his pupil at Edinburgh; stating also in an advertisement, that a part of his book was almost entirely due to Dr Macculloch. Under such circumstances, it is only reasonable to suppose, that he must have been fully acquainted with Playfair's Illustrations of Hutton, if not with the original Theory of the Earth,' on which many of Macculloch's speculations are founded. But, though Hutton is mentioned with respect, in a disquisition on the Origin of the Scottish formations,' at the end of the volume, it is quite clear that the author did not then appreciate his views; and it is well known that Dr Macculloch was far from being gratified by the manner in which his labours were made use of in this publication.†

In May 1822, Dr Boué began to publish, in the Journal de Physique,' a series of papers (afterwards united in a single volume) on the Geology of Germany; in which, combining the doctrines he had learned in Scotland with his practical knowledge of rocks, he threw light on many points in that country, till then difficult or obscure. The theory is here much sounder than in his former essay, and it is completely that of Dr Hutton; whose view of the phenomena attending the subterraneous intrusion of Trap-but no more-is referred to with proper acknowledgment; the author having previously published a different and erroneous opinion. These papers are distinguished by the reference of some of the trap-rocks and porphyries to distinct periods, determined by the members of the sedimentary series of strata, with which they are found to be connected ;-a step-of great importance, and an approach to M. De Beaumont's Epochs of Elevation,' already mentioned.

In 1823, there appeared in the Edinburgh Philosophical Journal,'§ a Comparative Geological View of the South-West and North of France, and the South of Germany,' by the same author, in which his Plutonic opinions are more distinctly unfolded; especially with regard to the granite veins, strikingly exhibited on the French side of the Pyrenees, in connexion with gneiss, and the (so-called) transition rocks.

Whoever,' says the writer, has seen the beautiful series of granitic veins which here cut, and sometimes support, the granite, will no longer

* See Ed. Phil. Journal, 1821. Vol. IV. p. 213.

See an account of this work of Dr Boué, in the Edin. Review, Vol. xxxviii. p. 413.

Géognostiches Gemalde von

doubt that the igneous origin of that rock is posterior to the slate formation. If the rock named Blaue Kuppe be a clear proof of the truth of the igneous theory respecting basalt, those places show that the true origin of granite also had been discovered by Hutton; and our respect for the views of this original thinker is increased by observing, that the masses of granular limestone seem to be in close dependence upon those of granite.

But,' he continues, Hutton furnished no explanation of the most difficult point, I mean the origin of gneiss, of crystalline slate, connected with transition state. The Pyrenees seem also to afford a hint of this particular process of nature. Gneiss is not, like granite, an igneous product. Viewing the crystalline slates as aggregate frag ments of more ancient rocks, or of the first oxidated crust of the earth,might it not be possible that igneous agents had, before, after, and simul taneously with the granite eruptions, acted upon the slates, and produced in them a kind of change? Heat and gaseous emanations would have given, especially under strong compression, a kind of igneous liquefaction to slate, similar to that observed by De Dree in his experi ments. The elements of the slates having lost a part of their cohesion, caloric and subterraneous emanations would have occupied the void spaces; chemical affinity would have exerted itself, within limits fixed by the force of cohesion,—and the constituent parts of rocks would have been able to assume, in the liquefaction or slow cooling, an arrangement more or less crystalline, according to the accessory circumstances, without losing much of their primitive slaty structure. This action of chemical affinities, assisted by foreign matter, introduced by a kind of sublimation, would have given rise to a number of species and sub-species of crystalline minerals disseminated in nests or in small veins.'-Pp. 131, 132.

Here, then, is the Metamorphic Theory claimed for himself by Dr Boué, who seems to have adopted also the hypothesis of sublimation, by which Von Buch explained the conversion of ordinary limestone into dolomite.

*

The paper just referred to was followed by a Memoir On the South-West of France,' &c., in the Annales des Sciences Naturelles, for 1824 and 1825, where these views are repeated; some of the passages being almost literally the same. But in this latter memoir the name of Dr Hutton is never mens tioned;-an omission which we are called upon to notice, as it is a justification of M. Brongniart's silence respecting Hutton's discoveries; and which is the more remarkable as Pallassou is often referred to, with a full acknowledgment of his merit and priority. Of this French memoir, the most important portion to the present

* Annales, &c., Tom. II. p. 387-123; Tom. III. pp. 55, 77, 299, 317; and Tom. IV. pp. 125-174.

*

enquiry is the first part, describing (chiefly from the observa tions of Pallassouf) a tract in South-Western France and the adjacent Pyrenees; where granite and other unstratified masses seem to alternate frequently with gneiss and mica-slate-in what had been considered as beds, but which the author regards as veins, intercalated by injection among the slaty strata. The most remarkable veins are those of La Cour, of Cierp, and Loucroup, places previously mentioned in the Edinburgh Journal'—and of the last Dr Boué gives a coloured section, which proves that they resemble those of Scotland;-the description of them, and of the altered fragments of slaty rocks which they frequently enclose, being perfectly Huttonian.

The author then goes on to state (pp. 417, 418,) the hypothesis already mentioned. The Pyrenees,' he says, 'suggest the idea 'that gneiss and mica-slate are no more than transition schists, 'changed and manufactured (travaillés) in many different ways by igneous agents, so as to present a crystalline character, while they retain their original foliated and stratified structure.' The detail which follows is nearly the same with what we have quoted from the Edinburgh Journal;' and the phenomena are precisely such as Dr Hutton had described in the passages from which we have above inserted extracts; many of them almost identical with those of the junctions, illustrated by Sir James Hall and Dr Macculloch ;-yet no one of these names is ever mentioned, or alluded to. § This total omission of reference on this subject, we cannot but regret; and we are prohibited from supposing it to be accidental, by a passage in a subsequent paper of Dr Boué, where he distinctly claims, for himself, the credit of the hypothesis, that the primary formations (meaning, we suppose, the most ancient crystalline slaty rocks) were of Neptunian origin, but repeatedly acted upon by fire.' || Here therefore, as before, in the Edinburgh Journal' we

* Annales, II., pp. 327-423; especially pp. 406, 407; 414-423. Memoires sur les Pyrenées, 1815, 1819, 1821.

Annales des Sc. Nat.: Tom. II. Allas, (in 4to,) Planche 18.— 'Filons granitiques au milieu des roches schisteuses cristallines: coupe exposée sur la grande route de Loucroup à Mongaillard.'

§ M. Boué, however, has referred more than once, in this French paper, to his Essay on Scotland, in which his obligations to Dr Macculloch are avowed.

Zeitschrift für Mineralogie, Jul. 1827. The passage stands thus in the author's French translation:- Ainsi l'on voit, qu' ayant le premier proposé de regarder le sol primaire comme un terrain Neptunien retravaille par les actions ignées, lorsque j'en vieus aux détails, j'ose à peine m'aventurer dans des conjectures, pour lesquelles j'ai été grande

have the Metamorphic Theory with numerous details ;-and we shall, without further comment, leave to the judgment of the reader, who is acquainted with no more than our preceding extracts from the pages of Dr Hutton, and who will compare them with the memoirs of Dr Boué-the question, whether the views in both are not essentially the same; not only in their general foundation upon the Plutonic theory, but in their application to the specific phenomena to which they have been directed.

The synoptical table of Formations, &c., published by Dr Boué in the Edinburgh Philosophical Journal' for 1825, which is nearly the same with that referred to by M. Brongniart, and the basis of Mr Lyell's arrangement, is a work of great merit ; exhibiting, we believe for the first time in a tabulated form, a correct view of the relations of the sedimentary and Plutonic groups of all ages, arranged in such a manner as to show distinctly their connexion; and enriched with a vast mass of condensed knowledge, respecting the distribution of those groups in the various countries of Europe, many of which the author's indefatigable activity had enabled him to examine in person. If this excellent work had been accompanied by a due acknowledgment of what had been done by his predecessors, the praise to which it is entitled would have been universal and unqualified. But as he claims for himself, both here and in his previous publications, a great deal of which the principles are clearly derived from Dr Hutton's Theory of the Earth,' it has become an act of duty to state the evidence upon which our opinion is founded. And this was the more necessary, since, from the fulness of the references which occur in many other parts of Dr Boué's valuable publications, we are persuaded that it is from some deception of judgment-or, most probably, from his not having been acquainted with the original work of Hutton-that he himself supposes that he claims no more than what is really his own. Our evidence, therefore, we have no doubt, will have the same effect upon his mind as upon those of our other readers; it will lead to enquiry and to the establishment of truth-which is all that a reviewer can effect or ought to desire.

It would appear that, to this hour, the merit of Hutton is but little known in France. In a collection of geological fragments, on the elevation of strata, published by M. Elie de Beaumont,†

ment dépassé par M. M. Backwell, Keferstein, De Beaumont, et De la Beche. Mémoires Géologiques et Paleontologiques; publiés par A. Boué. P. 48. Paris, 1832.

* Vol. XIII. p. 130, &c.

† Annal. des Sci. Nat.-Tom. XXV.