Now, as a contrast to this, let us see how the subject is managed in the conversational style, by the author under review. We quote from the opening of the first conversation, premising that the speakers are Mrs. R. and her two children, Edward and Christina, each of whom is characterised by peculiarities of sentiment and style of thinking.

"Edward.-Sea-shells, did you say, mother, in the heart of solid rocks, and far inland? There must surely be some mistake in this; at least it appears to me to be incredible.

"Mrs. R.-Incredible as you suppose it to be, my dear boy, you may see it with your own eyes in the marble of this chimney-piece, which you may perceive is throughout studded with shells, as if they were fresh from the sea. They even retain, as you perceive, their original nacre, as the French call the peculiar lustre of mother-of-pearl.

"Christina. Ah, so they do; but, I dare say, it is only a good imitation of shells made on the marble. There is a very pretty one on the lid of my work-box, which is certainly artificial; and those in the marble may have been done in the same way.

"Mrs. R. But, my dear, there is no nacre on the shell on your workbox; and it is evident, indeed, that it is wholly made of pieces of stained wood, ingeniously put together: but the shells in the marble are real shells, as you may see, differing in nothing from those we find on the seashore.

"Edward. Then how could they come into the marble? It must have been soft, like paste, or have been precipitated or deposited, as we say in chemistry, over the shells; for they are distributed, as I perceive, through its substance.

“ Mrs. R. — Yes; and if you were to break the marble into a thousand fragments, you would find a shell in almost every one of them.

"Christina. Is there any history of these curious shells, mother? I should like above all things to read it. I suppose it must be something like the stories I have seen of living toads found in the heart of growing

trees.

"Mrs. R.-The history of the shells, my dear, and many other things no less wonderful, is given in the science called GEOLOGY, which treats of the first appearance of rocks, mountains, vallies, lakes, and rivers, and the changes they have undergone from the creation and the deluge till the present time." (p. 3.)

As a considerable portion of the volume is devoted to the two rival theories of the earth, proposed by Hutton and by Werner, whose several disciples have been named Vulcanists and Neptunists, because the former advocates the agency of fire, and the latter the agency of water, in the formation of the crust of the earth, we shall give a short sketch of the leading doctrines of both systems, nearly in the words of our author:

.

For the purpose of making a globe like the earth, with seas, continents, and islands, diversified with hills and vallies, and productive of food for various animals, Dr. Hutton considered it as indispensable that other globes should have previously existed, from which materials for the structure might be derived. These supposititious worlds being acted on by the moist atmosphere, by rains, and by the frosts and thaws of winter and spring, would, in

a long course of years, be crumbled down, or, as the geologists say, disintegrated, and gradually carried by rivers, in the form of sand, clay, and gravel, to the sea. At the bottom of the sea these materials would arrange themselves in beds, differing in thickness, according to the circumstances by which they might be affected. But those beds would have continued in the soft state of sand or clay for ever, unless something occurred to harden them. It is here that Dr. Hutton brings in the agency of fire, and tells us, that there is at the bottom of the sea sufficient heat, from a great central fire which he conceives to exist in the centre of the globe, to melt all the clay, sand, and gravel, and to form them into rocks. He provides for the appearance of these above water, by supposing that the central fire occasionally expands itself, and elevates the newly formed rocks into islands and continents, diversified by hills and vallies; these being destined in their turn to the same changes of destruction and renovation, as those from which they took their origin.' (p. 47-50.)

According to the rival geological theorist, Werner, all the substances which now constitute rocks, mountains, and soil on the earth's surface, were originally existing, in a state of solution, in the waters of the great chaos, which he supposes at the beginning to have surrounded the globe to a vast depth. The substances or materials of rocks, thus swimming in the primitive ocean, he conceives to have gradually fallen to the bottom, sometimes by chemical, sometimes by mechanical means, and sometimes by both together; and in this manner, he thinks, all the rocks have been formed which we now find on digging into the earth. The inequalities of mountains and vallies on the surface of the earth, which were thus produced as soon as the waters began to subside (and this subsidence is an important point in the system), gradually rose out of the primitive sea, forming the first dry land. The rocks which were in this manner first formed, Werner calls the Original or Primitive Formation: they consist of granite, gneiss, different species of slate, marble, and trap.

"The formation of these rocks, however, did not, it seems, exhaust the materials floating in the waters, for the deposition went on, and a class of rocks were formed consisting of grey wacké, limestone, and trap, which rested on the primitive, and are called by Werner the Intermediate or Transition Rocks, because, on their appearance above the waters, the earth, he conceives, passed into a habitable state.

'After the formation of those primitive and transition rocks, Werner alleges that the water suddenly rose over them to a great height, covering them in many places, as it again subsided, with a new formation of rocks, consisting of sandstone, conglomerates, limestone, gypsum, chalk, and rocksalt, which he called Level or Floetz Rocks.

Since that period, the wearing down of the rocks, by the action of the weather and other causes, and the washing away of the worn materials by rains and streams of water, have formed soil, gravel, sand, peat, and the various other beds which are called Alluvial.' (p. 58-60.)

Into the details of these two systems, and the numerous objections to their several opinions, started and explained in the Conversations, we have not room to enter; and much less can we take up at present the still more rational and plausible system which Mr. Granville Penn has constructed from the Mosaic history of the creation and the deluge, and which is also fully treated of in the latter part of the volume. Our readers, however, may like to see a list of the subjects treated of in their order: these are, "Theories of the earth; Geolo

gical cabinet; First principles of the Wernerian system; Effects of expansion, arising from a central fire; Formation of ravines, vallies, and river courses; Origin of vallies, plains, marshes, bogs, and lakes; Order of rocks, with the origin of coal, and diffusion of gravel and sand in the sea; Consolidation and hardening of rocks; Mineral veins; Mosaic geology, as explained by Mr. Penn; Bones and shells in rocks and caverns, and in the soil; The great rock basins of London, Paris, and the Isle of Wight, with the extinct animals of a former world.”

It may be objected to these Conversations on Geology, that they contain too many objections, and leave many parts of the subject in utter uncertainty: but we may be permitted to reply to this, that all the systems of geology are precisely in the state in which they are here represented, uncertain and imperfect in their theories and speculations; though these are generally illustrated by interesting and well ascertained facts, and sufficiently plausible arguments. The author of the Conversations, therefore, it would appear to us, has acted judiciously in representing the actual imperfections of geology, rather than concealing them, and in expressing doubts upon points imperfectly ascertained, rather than dogmatising.

p.

ART. III. Catalogue of Works on Natural History, lately published, with some Notice of those considered the most interesting to British Naturalists.

FRANCE.

Fontenelle, M. Julia: Bibliothèque Physico-E'conomique, ou Journal des Découvertes et Perfectionnemens de l'Industrie Nationale et E'trangère, de l'E'conomie rurale et domestique, de la Physique, la Chimie, l'Histoire Naturelle, la Médecine domestique et vétérinaire, enfin des Sciences et des Arts qui se rattachent aux besoins de la vie.

Among the collaborateurs in this extensive and important undertaking we perceive the distinguished names of Baudrillart, Bory de St. Vincent, Delille, Deyeux, Guillemin, Labarraque, Lassaigne, Lesson, Pelletan, Raspail, Richard, Tollard, Vergnaud, &c. &c.

Vatel, M. P., Médecin-vétérinaire: E'lémens de Pathologie Vétérinaire, ou Précis théorique et pratique de la médecine et de la chirurgie des principaux animaux domestique. Tom. 2. 1e et 2e parties. Paris, 1828. 2 vols. 8vo, pp. 935.

Bois-Duval, M. J. A., Membre de plusieurs Sociétés savantes: Flore Française, ou Description synoptique des plantes qui croissent naturellement sur le sol Français. Paris, 1828. 3 vols. 18mo, pp. 1120.

Ternaux, M., ainé: Sur les

des Mérinos en France.

Obstacles qui s'opposent encore à la Propagation
Paris, 1828, 4to.

This work contains curious facts respecting sheep.

Macquart, M. J.: Insectes Diptères du Nord de la France (Platypézines, Dolichopodes, Empides, Hybotides). Lille, 1827. 8vo, pp. 159, avec pl. Bory de St. Vincent, M. le Colonel: Résumé d'Erpetologie, ou d'Histoire Naturelle de Reptiles, accompagnée d'une Iconographie. 1 vol. 18m0, avec atlas, 18mo.

An exceedingly interesting and instructive production, by one of the first naturalists in France.

GERMANY.

Kreysig, Frédéric Louis: Ueber den Gebrauch der natürlichen und künstlichen Mineralwässer. Leipzig, 1828. 12mo, pp. 330.

This little work contains an account of the mineral waters of Carlsbad, Embs, Eger, Marienbad, Pyrmont, and Spa.

Mencke, Dr. C. Th.: Synopsis Methodica Molluscorum generum omnium et Specierum earum quæ in Museo Menkeano adservantur. Pyrmont, 1828. 8vo, pp. xii. et 91.

Harsweg, M.: Hortus Carlsruhanus, oder Verzeichniss sœmmtlicher Gewächse, &c. Carlsruhe.

8vo.

Transactions of the General Helvetic Society of Natural History: Verhandlungen der Allg. Schweizer, Gesellschaft, &c. Zurich. 8vo, pp. 160. Perleb, M. C.: Lehrbuch der Naturgeschichte, &c. Elements of Natural History.

Leichtenstern, M. de: Umriss der Naturbeschreibung, &c. Elements of Natural History, &c. Berlin. 8vo, pp. 200.

Bluff, M.J.: Entwickelungs-Combinationen Organischer Wesen. Cologne. 8vo, pp. 51.

Duvernay, Dr. G. L: Discours prononcé le 22 Décembre, à l'Ouverture du Cours d'Histoire Naturelle de la Faculté des Sciences de Strasbourg. Strasburg, 1828. 8vo, pp. 418.

HOLLAND AND THE NETHERLANDS.

Anslijn, M. N.: Natuurk. Verhandel., &c. Catalogue of the Insects of the Netherlands, particularly those found in the vicinity of Harlem. 1828. Tom. 16. pt. 1. pp. 125.

Lejeune. M. A. L. St.: Revue de la Flore des Environs de Spa. Liége 8vo, pp. 263.

ART. IV. Literary Notice.

THE Arcana of Science and Art for 1829 will be published early in January, and will contain all the popular discoveries and improvements of the past year, in mechanical and chemical science, natural history, rural and domestic economy, the useful and fine arts, and a miscellaneous register. The forthcoming volume will be somewhat larger than that of last year, and will be illustrated with upwards of twenty engravings.

EPINAL, Oct. 15. There is a small miscellaneous Museum here, but it is more remarkable for Roman sculptures and coins dug up in the neighbourhood, than for specimens of natural history. The attention to this science, however, is increasing, as appears both by the specimens lately purchased and added to the collection, and by the communications to a very useful periodical which appears here every three months, Le Journal de la Société d' Emulation. There is a tolerable collection of minerals, and a number of precious stones of different kinds procured from the shrines of saints, or sacred relics of monasteries or convents, formerly existing in the department of the Vosges. A number of pearls have lately been taken from the fresh-water muscle (Mỳa margaritífera), found here in the river Valogne ; and when the Duchess of Angouleme, who lately visited Epinal, saw those in the museum, she very patriotically ordered a necklace from the director and librarian, M. Petit-Jean, a liberal minded excellent man, who seemed to us to unite the best parts of the French and English character.

Strasburg, Oct. 19. -The Museum of Natural History here contains an extensive collection. It is more than usually rich in corals, sponges, star-fish, and marine Mollúsca. There is an excellent specimen of Astèrias càput Medusa, a great number of Gorgònia, of Scalària speciòsa, and of Cypraea, and a pair of gloves manufactured from the fibres of Pinna nóbilis. There is an excellent collection of birds, especially those of Alsatia, which is rich in this division of animals, and contains some species found but in few other countries. Several species of owls, birds in which Alsatia is very prolific. Strix uralensis (the owl of the Ural mountains), rare, and worth fifty Napoleons. Cérthia murària, only found in Alsatia. Trochilidæ, a large collection. Charadrius gallicus and Phænicópterus rùber, found on the banks of the Rhine. A considerable collection of fishes. Diodon maculatus. A good specimen of the rattle-snake. Sorex moscellàtus, from Siberia, very rare, presented by Pallas. Myrmecóphaga jubàta, the anteater, a remarkably fine specimen. Sciurópterus volucélla. One of the best collections of butterflies in existence out of Paris and Vienna; and the same may be said of the collection of organic remains, and petrified productions. Physèter macrocéphalus, the head and part of the vertebræ. Large fragments of mammoths, elephants, hyenas, and other fossil quadrupeds. A good collection of minerals. Hyàlia roulé, a species of quartz found in the Rhine, but rare. A collection of the minerals of Alsatia, with those which have been applied to purposes of utility particularly indicated.

An apartment devoted to vegetable productions, contains the section of the trunk of a silver fir tree (Abies pícea), called Le grand Sapin de Hochwald, a forest at Barr, in Alsatia. This tree was 150 ft. high, with a trunk perfectly straight and free from branches to the height of 50 ft., after which it was forked with the one shoot 100 ft. long, and the other somewhat shorter. The diameter of the trunk at the surface of the ground was 8 ft.; at 50 ft.