the observation of Dr. Hutton as tending to evince the long period during which the surface of the earth has at various times been subjected to the mechanical action of water. It was at Bromsgrove near Birmingham that this observation was made. The pudding-stone discovers itself in several bays south-west from Swansea to Burry River.

"In this direction," says Mr. Townsend, " between the Mumbles and Wormshead, are four high mountains, Caven Brane, Llanmadoc, Caliver, and Rosilly, entirely composed of siliceous breccia and pudding-stone, rising through mountain lime-stone. Each of these are long ridges, which, viewed in one direction, appear conical. The charge is composed of white quartz crystals, which are not merely in contact with each other, but frequently the convex surface of one coincides with the concave surface of the other. Caliver has large rocks, resembling petrosilex, and containing zeolite.” (P. 180, 181.)

But what is most important with respect to pudding-stone is, that it forms the places where its beds rise in the neighbourhood of the primitive strata into an inclined position; we follow it into the valleys and plains; we observe it to continue and gradually to assume a more level position, until at length we recognize in it all the characters of the old red sand-stone of the Werneric series. It runs from the feet of the mountains through the middle tract of England, until it reaches the boundary of the level strata, of which we have spoken above.

On this stratum the coal formations of our island rest. The coal together with the grit rock and argillaceous stone containing it, occupies distinct fields or basins, which affect an elliptical form, and are shut in or enclosed on every side by that rock which is termed by Mr. Townsend mountain lime-stone. The account which he has given of these coal fields is one of the most interesting parts of his work, and is in some measure new to the public. He has in several instances traced the mountain lime-stone round the borders of the coal fields. On every side its beds are inclined towards a common centre, and on these the grit or micaceous sand-stones which, together with the argillaceous stones called duns, enclose the seams of coal, rest in a conformablė position.

The inclination of these rocks is very various. On these irregular and often disjointed strata the horizontal beds of red marl are deposited. Over them again lie the beds of lyas, and the series of formations which we have before enumerated thus be gins. Thus we find that the coal fields in Britain occupy that tract of country which has been termed the Middle Region, and which intervenes between the mountainous districts and the level plains stretching over all the eastern counties.

The more detailed account of the strata in this island prepares · 3

us to contemplate with interest the succession of formations in other countries. Under this head our author has given us his own observations, and a collection of the brief notices afforded by other travellers in almost every part of the world which has been explored by Europeans. They are very general, but exceedingly scanty and deficient in particulars, yet they are sufficient to justify the conclusion which Mr. Townsend has drawn

from them.

"Whether we examine," he observes, "Europe, Asia, Africa, or America, the same arrangement may be traced; with this exception, that both in our island, and over the surface of the globe, in some places, the superior strata are deficient, and may be supposed to have been carried off, after they had been deposited in the bosom of the ocean.

"This arrangement, as already stated, includes granite, gneiss, slate, and argillaceous schist, mountain lime-stone, coal, schist, calcareous rocks, with clay, sand, chalk, and its integument of sand and clay.” (P. 122.)

When we consider that the same general features have been traced over so great a portion of the surface of our globe, and that in all the tracts which have been carefully examined by naturalists, as throughout Germany, Scandinavia, the Alps, Italy, Sicily, Spain, and South America, a surprising uniformity has been remarked, even in the details of the geological succession; that in these countries not only all the great formations are known to exist in their proper series, but even the subordinate ones accompanied by their peculiar minerals, we certainly are authorized in considering the true theory of the earth as a thing not to be despaired of. "Nature," says Von Buch, "resembles herself. She is the same in the northern and in the southern regions; and her laws are general throughout the surface of the earth." We may remark, that the general observations of Mr. Townsend are in accord with the succession of formations pointed out by the Professor of Freyberg; though as the objects pursued by these philosophers are considerably different, the points of relation between them are not very extensive.

In order to form an estimate of the merits of the remaining parts of this work, we must contemplate them under two points of view, in some measure distinct: first, as leading to a particular geological theory, or at least endeavouring to account for the principal phenomena which have previously been offered to our view: and, secondly, as furnishing proofs of an universal deluge. Before we can understand, and correctly appreciate, Mr. Townsend's geological opinions, it will be necessary to state in a few words the leading positions of the two opposite theories which are maintained by the cosmogonists of this country.

It appears to be fully agreed on all hands that the strata which

the crust of the earth were deposited by the ocean. compose This fact is evident on the most careless inspection. It is, however, disputed, how far the deposition was chemical, and how far mechanical. The Neptunians consider all the older strata as chemical depositions, or as crystallizations from a chemical solution. The Huttonians view all the strata as mechanical debris carried down by rivers, and reduced to a level surface at the bottom of the ocean by the action of its waters. The main difference, however, between these philosophers, turns on the two following points; first, by what cause has the hardening or consolidation of the strata been effected? Secondly, by what means has the bed of the ancient ocean become elevated, so as to form the continents which are the present seat of the animal and vegetable

creation.

With respect to the consolidating power, Dr. Hutton thought it could be determined by examining the composition of rocks, and pronounced that it was not water. An aqueous menstruum, he observes, always leaves pores or interstices in the crystallizations formed in it. Solid rocks, therefore, are not so produced. He refers the whole effect to fire. All the rocky strata of our globe have, according to him, undergone igneous fusion, since they were deposited at the bottom of the sea. The Neptunians refer the consolidation of strata entirely to the action of water.

The elevation of the strata above the surface of the ocean is attributed by the Huttonians to the agency of the same power which effected their consolidation, namely, a fire existing and continually operating in the interior of the earth. Elastic vapours are extricated by the central heat which lift up whole continents above the level of the ocean. According to Hutton, a continual renovation of the earth proceeds on this principle. Tides and rivers carry away disintegrated masses into the bed of the sea, where they are elaborated by water and fire, and formed into new tracts, which are at length to be raised, and to serve as the future habitations of men. The Neptunians acknowledge the existence of no such subterraneous operations, but they refer the change of level in the ocean to a cause which is as difficult to conceive as that assigned by the Huttonians. They suppose that the water of the ocean originally covered the highest mountains, and that the sea has actually subsided as the strata of the earth were deposited in its bosom. They have never explained to us what has become of the immense body of water supposed to have disappeared.

There are two sets of rocks, concerning the nature of which keen disputes are agitated between the contending parties. The Huttonians find in these evidence of all their assertions; they discover in their structure the most decided proofs of igneous

fusion; and particularly they regard them as the agents of the second great phenomenon, the elevation of the strata from the bowels of the earth. The Neptunians, strange to say, can discern nothing of all this. They affirm that the rocks in question are quiet deposits of the ocean, as evidently as any other class of mineral bodies.

The trapp rocks bear a strong analogy to the products of volcanoes. Basalt, indeed, has so fortunate a resemblance to lava, that all the keen eyes of the Wernerian School have never yet been able to detect any characteristic and universal distinction between them. They are, however, not the less resolute in maintaining their position, that all trapp rocks are of aqueous origin, and therefore afford no assistance whatever to the Huttonians. Very lately the dispute has taken a different turn. D'Aubuisson, an excellent mineralogist of the Wernerian School, and strongly attached to the principles of his illustrious master, undertook a journey to Saxony, for the purpose of examining that range of mountains termed the Erzgebirge, which divide Saxony and Bohemia, the summits of which consist of basalt and other trappean rocks, and have been supposed to be the remains of effete volcanoes. He returned fully satisfied of the aqueous origin of the whole range; and a great triumph was considered to be gained by the Neptunians. Having, however, at a subsequent period, at the request of some strenuous vulcanists, surveyed the district of Auvergne, which abounds in basaltic rocks, D'Aubuisson has declared his perfect conviction that the trapp formations in that country had a volcanic origin. On the whole, it must be considered that this investigation has turned out in a manner very favourable to the volcanists and Huttonians, especially as the volcanic rocks of Auvergne are found to rest on granite; and it is thus proved, agreeably to the favourite assertion of those philosophers, that these matters are thrown up by fire from beneath the primitive strata. This event, of great importance, as we shall presently observe, to the theory adopted by Mr. Townsend, happened, or at least has become known to this country, since the publication of his work.

Secondly, the Huttonians not only claim a volcanic origin for basalt, in which it appears that they are not without good grounds; they assert granite also to be the product of fire. Granite every where lies under all the other rocks; it is regarded by Hutton as the chief agent in lifting up the stratified masses of the earth from the subterranean cauldron, where they had been previously melted. Instead of being the most ancient of all rocks, as the Neptunians suppose, Hutton affirms it to be the newest of all. He imagines it to have been violently injected in a melted state by the force of the internal heat under the mass of strata, and to

have raised them up from the abyss. Accordingly he always denied the stratification of granite, which would have been fatal to his system in this particular; but the researches of geologists since his time have not been favourable to his views. The celebrated Alpine traveller, Saussure, proved that the granite of the central Alps is disposed in distinct strata: the same fact has been observed elsewhere; and Mr. Playfair, the most distinguished advocate of the Huttonian theory, has been forced to acknowledge that the greater part of granitic mountains are stratified; they must therefore be regarded as deposits of the ocean.

Mr. Townsend belongs to a class of philosophers who go between the two extremes of the Huttonian and Wernerian hypotheses. They are very numerous on the Continent; but in this country their system has of late years found no advocates, though it appears to have been first proposed by an Englishman-the excellent Dr. Ray. Lazzaro, Moro, Pallas, Voigt, and Dolomieu, are the most celebrated names in the list of the volcanists. They hold the same opinions on the leading points, but are not at all agreed with respect to a number of subordinate questions.

We shall pursue the steps of our author, and shall be enabled to appretiate his arguments, after the survey we have taken of the disputed ground.

First, with respect to the consolidation of strata, Mr. Townsend entirely adopts the Wernerian doctrine, and advances some convincing proofs of its truth. No person who has attended much to the appearances presented by extraneous fossils or petrified bodies in the earth, can entertain a doubt that water, either mechanically or chemically, conveys the particles of silex and other rocks in such a state as to allow of their crystallizing according to their peculiar forms. In the green sand stratum of Pewsy Vale, a hard sand rock is formed by the consolidation of the sand. That water was the agent is proved by the agatized corals and pectinites in which the shell has been washed away, and the vacuity occupied by silex. In many, although the valves seem to be perfect, yet when broken they appear to have only a coating of flint, and to be hollow within. From this circumstance, and from many others well known to those who are conversant in organic remains, we may collect that petrifaction is performed by the gradual infiltration of lapidific juices in solution, and not by the violent injection of melted matter. The consolidation of the rocks in which these fossils are found must be assigned to the same cause. We have not sufficient space for further remarks on this interesting subject, but must refer our readers to Mr. Townsend's chapters on the consolidation of strata, and to his remarks on the Huttonian hypothesis; where they will find enough to satisfy any scruples they may entertain on this head.