in Cornwall in 1800, amounted to 99; of which 45 were of copper, 28 of tin, 18 of copper and tin, 2 of lead; the rest produced silver, cobalt, and antimony; and at present some mines of manganese are opened. To this paper and to another, by the same author, on the geology of some parts of Hampshire and Dorsetshire, tables of the heights of places above the level of the sea, by barometrical admeasurements, are annexed.

The eighth paper, on the Wrekin and the great Coalfield of Shropshire, by Arthur Aikin, Esq. displays great ability, and is of considerable importance, by adding to our knowledge of the extent and situation of those deposits of fuel, on which the commercial advantages of this kingdom so much depend. The great Shropshire coal-formation lies adjacent to the old and red sandstone, which occupies so large a portion of the north western part of England, and to which the rock-salt district is subordinate. At the Madely Colliery, a pit has been sunk through all the beds to the depth of 729 feet: they are there no less than 86 in number, but vary, as in most other coal fields: for it is certain, notwithstanding the frequent representations to the contrary, that beds of coal and the intervening strata, are liable to very considerable alterations in thickness, though their increase or decrease is generally so gradual, as not to be perceptible in the works of each separate mine. Mr. Aikin is mistaken in referring the peculiar configuration of the curl-stone to an animal origin; it occurs in the common argillaceous ironstone after torrefaction, and is well described by Mr. Martin in his Petrificata Derbiensia. (Plate 27.fig. 4.) The coal formation rests upon a limestone, which appears to be identified with that of Dudley by the occurrence of the entomolithus paradoxus. The great mass of the Wrekin, the Lawley, Caer Caradoc, &c. consist of an unstratified trapformation,' comprising felspar, and green-stone rocks, the latter of which affect the magnetic needle.

These rocks are incumbent on highly elevated strata of transition slate on the eastern side of this mass it appears, That there is a great deposit of stratified rocks, consisting of quarry grit; of a micaceous sandstone, nearly allied to greenstone; of a sandy slate-clay; of limestone, slaty marle, and sandstone slate, in alternating beds; and of the independent coal-formation; all rising up parallel, or nearly so, with the trap at a horizontal angle, the magnitude of which decreases, in proportion to the distance of each bed from the trap... That on the western side the mass of deposits is very small, consisting of a sandstone composed of angular fragments, on which rests a thin, broken coal formation: That the old red sandstone bounds the whole of this series of rocks on the east, north, and north-west, but though in contact, appears to be perfectly unconnected with them.' p. 212.

The amygdaloid containing in its vesicles concretions of

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glassy actynolite, is noticed as a singular and little known mineralogical production of this trap formation.

Dr. William Fitton's Notice respecting the geological structure of the viciuity of Dublin; with an account of some rare minerals found in Ireland,' in the 11th paper, is interesting, but, for want of attention to the geognostic relations of the various rocks, unsatisfactory. Limestone, granite, the Quarry rock of the Sugar loaf, Bray head and Shank hill, and a trap formation near Ballinascorney, are the most remarkable features. The minerals which are enumerated as the production of Ireland are-vesuvian, grenatite, beryl, andalusite, a crystallized mineral resembling indurated talc, hollow spar, pitchstone, granular sulphate of barytes, and wavellite.

On the Mineralogy of the Malvern Hills, by Leonard Horner, Esq. This paper (the 12th.) contains a minute descrip. tion of the various rocks which form this ridge, and their resative situation. The higher part consists of unstratified masses of granitic rock, exhibiting various combinations of felspar, quarz, mica, hornblende and epidote; the western declivity presents strata of limestone, and of an argillaceous stone containing nodules of limestone, but considerably resembling grauwacke. These strata are all very much elevated and sometimes vertical; they form a continued succession of hills, and their respective bearings differ, in different places, though they generally range N. and S. parallel to the granitic chain. On the eastern side, the granitic rocks descend to an extensive plain of red sand stone, the strata of which are horizontal. These phenomena the author endeavours to explain, according to the Huttonian hypothesis, by supposing the moveable mass of granite to have acted in a direction from W. to E; and in bursting through the superincumbent strata to have elevated, and partly overturned, the strata to the West. Its strength being in this manner exhausted, the country to the East remained in the same state as before. The application has evidently a degree of plausibility in this instance, though we do not doubt that the facts admit of an explanation on opposite principles. We however agree with Mr. Horner in his concluding remark.

If the geologist strictly guards himself against the influence of theory in his observations of nature, and faithfully records what he has seen, there is no danger of his checking the progress of science, however much he may indulge in the speculative view of his subject.' p. 321.

The 13th paper is a short notice accompanying a Section of Heligoland drawn up from the communication of Lieu tenants Dickinson and Mac Culloch, of the Royal Engineers,

by Dr. J. Mac Culloch. The structure of the island seems peculiarly simple, consisting of alternating beds of indurated clay and grey limestone, inclined to the N. E. at an angle of 30° with the horizon.

In the fourteenth paper, Mr. Parkinson communicates some observations on the Strata in the neighbourhood of London, and on the fossil remains contained in them. The author agrees with Mr. Farey, Mr. Smith, &c. in supposing the strata surrounding the metropolis to be the most recent in this kingdom. He observes that

Real alluvial fossil, washed out of lifted or original superior strata by strong currents, and which in other parts are very abundant, are rarely seen in the countries adjacent to the metropolis. This remark is necessary, since those widely extended beds of sand and gravel, with sandy clay sometimes intermixed and sometimes interposed, and which have been generally considered as alluvial beds, are here assumed to be the last or newest strata of this island, slowly deposited by a pre-existent ocean.' p. 327.

The idea, that the pebbles of the vicinity of London' have not been rounded by rolling, but that they owe their figures to the circumstances under which they were originally formed,' and that they have each been produced by a distinct chemical formation, which, it may be safely concluded, from the remains of marine animals so frequently found in them, took place at the bottom of the sea while these animals were yet living-Mc. Parkinson endeavours to prove by the crystalline appearance of the attendant beds of sand, and by the perfect state of the marks of petrifactions' on their surfaces; but he appears to us wholly unsuccessful. Where these pebbles are mixed with the ramose flints and other fossils found in chalk, it is evidently most natural to suppose, that the mixture has been formed by the agency of water from the debris of one or two strata; but admitting that these uniform oval pebbles form exclusively a stratum, as at Woolwich, Blackheath, Plumstead, &c. where scarcely a ramose flint is to be found: either they were brought thither by the agency of water from some other place, or they were (as our author seems to hint) formed on the spot, a deposition from the water. If the former was the case, it would be much more difficult to shew how the removal could take place without a degree of friction, tending to produce the form which they now have, whatever their original figure may have been, than to admit that this friction was sufficient to produce that form altogether. if, on the contrary, they were formed where they at present exist, the impression of shells, &c. which they exhibit, ought to correspond with the shells now mixed among them; and as these impressions are mostly external,

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we might reasonably expect to find the shell occasioning it, adjacent or adherent: but the impressions indicate anomiæ, or rather tenebratulæ, echini and alcyonia; genera not found among the shells interspersed between the pebbles, which present ostreæ, cerithiæ, turritellæ, cyclades, &c. It therefore appears very evident to us, that the animals to which the petrifactions in the pebbles owe their origin, and those to which the exuvia interspersed among them belong, could not have existed at the same time: nor do we see any sufficient difference between the fossils of the pebbles and those of the chalk stratum, to justify the supposition of a different formation from that which deposited the chalk, though such a difference may possibly be found. The angular sand does not prove that it is a crystalline deposition; since varied modifications of the size and motion of the bodies which produce sand by friction and contusion, break the fragments with an irregular conchoidal fracture, or split them according to the directions of their crystalline lamina, or merely reduce them to minute pebbles by rubbing off the corners. The uninjured state of the impressions on the surface, appears, from the instances which we have seen, to be owing to the protection afforded by the projecting edges. When to these circumstances we add, that the internal structure of these pebbles affords no symptom of concretion or crystalline aggregation, we must, at least for the present, withhold our assent from Mr. Parkinson's hypothesis, and suppose that the beds of sand, gravel, and clay, deposited upon the chalk stratum, are the detritus of higher strata in which the fossils of the pebbles had previously been enveloped, by an ocean inhabited by those genera whose preserved remains are mixed with them. This supposition gains additional probability from the circumstance that, iu France, strata of sand and sand stone occur, differing materially from the sand, gravel and clay strata resting upon the chalk formation in our own country. We must, however, do Mr. Parkinson the justice to say, that the value of his excellent paper is by no means diminished by the introduction of this hypothesis. He has candidly exhibited the appearances of nature, and the application which he has made of his extensive knowledge of fossil reliquia to the elucidation of the various beds which pass under his review, makes us wish to see many other strata described with equal accuracy. There will then be some prospect of judging of the various formations, when they are identified by their respective inhabitants.

The 'Sketch of the Geology of Made'ra,' by the Hon. H. G. Bennet, throws some light upon the formation of this island, which appears to be strictly volcanic, consisting of vas rious beds of lava.

The most interesting geological facts are; 1st, the intersection of the lava by dykes at right angles with the strata. 2dly, The rapid dips the strata make, particularly the overlaying of that of the Brazen Head, to the eastward of Funchal, where the blue, grey and red lavas are rolled up in one mass, and lie in a position as if they had slipped together from an upper stratom. 3dly, The columnar form of the lava itself, reposing on, and being covered by, beds of scoriæ, ashes and pumice, which affords a strong argument for the volcanic origin of the columns themselves : and 4thly, The veins of carbonate of lime and zeolite, which are not found here in solitary pieces as in the vicinity of Etna and Vesuvius, but are amid the lavas and in the strata of pumice and tufa, and are diffused on the lava itself, and occasionally crystallized in its cavities.' p. 398.

Our limits permit us only to add a very brief notice of the contents of the remaining papers. The second by Mr. Phillips contains a Description of the veins of the Red Oxyd of Copper, and the manner in which that curious mineral was found. A mineralogical description of the substance is given, and six modifications of its primitive crystal, with their varieties, enumerated and figured. The fifth and fifteenth are by Count de Bournon on the laumonite and bardiglione, or anhydrous sulphate of lime. The former mineral, also called efflorescent zeolite, has not been chemically analysed, but its crystallographical characters are very distinct, and are investigated by the Count with his usual ability. It is also distinguished by its speedy decomposition when exposed to the air, and is found generally attendant upon zeolite. Fourteen modifications of its crystal are represented. Bardiglione, or anhydrous sulphate of lime, differs from gypsum in being destitute of water, harder, and of a different crystallization. Like gypsum it appears to affect the rock-salt strata. In distinguishing it from plaster, the Count sketches a theory of the nature of that substance, which to us appears visionary. In order to explain the crystallizations of various substances, it may be convenient to refer them to an integrant molecule' of certain angles and dimensions; but there is obvoiusly great risk of error, in attempting to deduce the physical properties of a substance from a principle which was merely geometrically inferred. Nor do we think, that the ideas of imperfect integrant molecules, and hollow integrant molecules are strictly philosophical.

The ninth paper contains an elaborate Analysis of an Aluminous Chalybeate Spring in the Isle of Wight by Dr. A. Marcet. This mineral water is distinguished by its extraordinary strength. It contains 107,4 grains of ingredients (principally sulphat of iron, sulphat of alumine, and sulphat of soda) in the pint; and the method pursued by Dr. Marcet to obtain them, may be esteemed a perfect specimen