Again, after enumerating in detail the several descriptions of stratified rocks, he adds "And under these is granite, which nowhere appears to be stratified. “Thus we have two classes of rocks, stratified and unstratified, which will require distinct examination." "In each of the localities specified, the series of strata is found to be constant, not that every particular stratum is every where observed; but the order in which they succeed one another, when present together, is never reversed. This is consistent with all experience." And in conclusion from this scientific writer— "The true scale of geological chronology is that of the stratified rocks. According to the view previously advocated, the several systems of strata mark periods more or less exactly definable; the last, or supertertiary, which descends to the present era of the globe, being, as yet, one of the least defined in its limits. "At present, the chronology of the globe, starting from the origin of the stratified rocks, and including the whole series of successions of organic beings, and all the convulsive disturbances of the cooled and consolidated crust, recognises many successive periods of unknown duration. Neither does it appear possible to know their duration, or even the limits of error within which they fall. How, then, it may be asked, do geologists justify their confident assertions. of the very great antiquity of particular rocks, as compared with the few thousand years of history? To this the reply is simple. Many of the ancient stratified rocks were formed in the sea, by processes perfectly similar to those which go on at this day; and, in some cases, we may believe not at all more rapid in their effects. "The laminated sandstones often mark what appears to be the ripple of a gentle tide, and the successive deposits of agitated water; the shelly limestones sometimes prove very slow deposition of even a single layer of calcareous rock; the alternation of igneous and sedimentary rocks gives us the similitude of volcanic submarine eruptions. Now, if we compare, with the sedimentary strata of any particular period, the most similar products of the present day, we shall be impressed with the necessity of allowing a long period for the production of a single stratified formation.* Treatise on Geology, pp. 30-33, 291, 292. We are furnished, from another branch of science, with a remarkable corroboration of the general tendency to a stratiform arrangement of the mineral components of the earth's crust. Mrs. Somerville, when treating of the form of the earth and its polar compression, employs the following as one of the evidences in favour of her argument: "The regularity with which the observed variation, in the length of the pendulum, follows the law of the square of the sine of the latitude, proves the strata to be elliptical, and symmetrically disposed round the centre of gravity of the earth, which affords a strong presumption in favour of its original fluidity."* M. de la Beche says— "In the accompanying table, rocks are first divided into stratified and unstratified, a natural division, or, at all events, one convenient for practical purposes. "The same may, perhaps, also be said of the next great division; namely, that of the stratified rocks into superior, or fossiliferous, and inferior, or non-fossiliferous. The superior stratified, or fossiliferous rocks are divided into nine groups. "In a descending series these are:-1. Modern; 2. Erratic Block Group; 3. Supra-cretaceous; 4. Cretaceous; 5. Oolitic; 6. Red Sandstone; 7. Carboniferous; 8. Grauwacke; and 9. Lower Fossiliferous; and underneath them all, the Inferior or Non-fossiliferous strata."+ M. de la Beche's work, from its design, being necessarily descriptive, should our readers desire fuller information from that correct geologist, they will require to peruse the work itself, as the stratified rocks and their embedded fossils occupy nearly the whole treatise. With these facts, obtained from so many and from such unquestionable authorities, fresh upon the mind, let us recur to what is stated in the seventeenth Theorem. "That from the evidence afforded by the position and dislocation of the stratified masses, it is considered, that they have been elevated from where they were originally deposited, into * Connexion of the Sciences, pp. 62, 63. + Manual, pp. 34-37. the inclined positions they now occupy; and by the agency of a force which acted from below upwards. And, that the time occupied in their elevation was very brief comparatively with that which elapsed during their formation. The following are some of the evidences for these opinions: Mr. Lyell boldly commences It has already been “LAND has been raised, not the sea lowered. stated, that the aqueous rocks, containing marine fossils, extend over wide continental tracts, and are seen in mountain chains rising to great heights above the level of the sea. Hence it follows, that what is now dry land was once under water. But if we admit this conclusion, we must imagine either that there has been a general lowering of the waters of the ocean, or, that the solid rocks, once covered by water, have been raised up bodily out of the sea, and have thus become dry land. The earlier geologists embraced the former opinion, assuming that the ocean was originally universal, and had gradually sunk down to its actual level, so that the present islands and continents were left dry." After enumerating the difficulties in which this involved. them, Mr. Lyell goes on to say * ..... "Geologists, therefore, were at last compelled to have recourse to the other alternative, namely, the doctrine that the solid land has been repeatedly moved upwards or downwards, so as permanently to change its position relatively to the sea. These preliminary remarks will prepare the reader to understand the great theoretical interest attached to all facts connected with the position of strata, whether horizontal or inclined, curved or vertical. . . . The most unequivocal evidence of a change in the original position of strata is afforded by their standing up perpendicularly on their edges, which is by no means a rare phenomena, especially in mountainous countries. . . Vertical strata, when they can. be traced continuously upwards or downwards for some depth, are almost invariably seen to be parts of great curves, which may have a diameter of a few yards, or of several miles. "I may now recapitulate a few of the conclusions to which we have arrived: The dry land consists, in a great part, of strata formed originally at the bottom of the sea, and has been made to arrange and attain its present height by a force acting from beneath." This we of course dissent from. And in conclusion, from Mr. Lyell, he continues, towards the end of his work "If we admit that solid hypogene rocks, whether stratified or unstratified, have in such cases been driven upwards, so as to pierce through yielding sedimentary deposits, we shall be enabled to account for many geological appearances otherwise inexplicable."* Professor Buckland says "The actual position of these beds (the stratified masses of rock) is generally more or less inclined to the horizontal plane, though often under an angle almost imperceptible. By this arrangement many strata, affording numerous varieties of mineral productions, are made to emerge in succession on the surface of the earth."+ Professor Phillips asserts "We are fully convinced, that for broad and extensive formations of strata, composed of various successions of sands, clays, and limestones, variously stored with organic remains, there can be no risk of error in assuming, as a fact sufficiently proved, that they were deposited nearly level. Assured of this fact, as a basis of reasoning, we may proceed to enquire into the actual position of strata, as they are seen in the dessicated parts of the old oceanic bed which now compose our solid land. The most general condition of the stratified rocks of all ages is to be not quite level, but inclined to the horizon in some one direction, and at some certain angle, in each locality. "By a careful study of the circumstances, we observe, that these indications of disturbances augment continually towards the axis or centre of the mountain group; and that the direction of the movements has been there upwards. There has, in fact, been a real and violent elevation of the stratified crust of the globe, corresponding to the centre or axis of each mountain group. The "We are thus led to associate the phenomena of the disturbance of strata with the eruption of crystallized rock from beneath. latter, however, is not the cause of the former, but rather a concomitant effect of some general dynamical agency.+ Professor Playfair, in his illustrations of his friend Mr. Hutton's Geological Theory, gives the following graphic passage: * Elements, vol. i. pp. 94-96, 101, 102, 146, 147. vol. ii. pp. 370, 371. "We have seen," says he, "of what material the strata are composed, and by what power they have been consolidated; we are next to enquire from what cause it proceeds, that they are now so far removed from the region which they originally occupied, and wherefore, from being all covered by the ocean, they are at present raised, in many places, 15,000ft. above its surface. Whether this great change of relative place can be best accounted for by the depression of the sea, or the elevation of the strata themselves, remains to be considered. Of these two suppositions, the former, at first sight, seems the most probable, and we feel less reluctance to suppose, that a fluid, so unstable as the ocean, has undergone the great revolution here referred to, than that the solid foundations of the land have moved a single fathom from their place. This, however, is a mere illusion. Such a depression of the level of the sea as is here supposed, could not happen without a change, proportionally great, in the solid part of the globe; and, though admitted as true, will be found very inadequate to explain the present condition of the strata. It is certain that many of the strata have been moved angularly, because that, in their original position they must have been all nearly horizontal. Loose materials, such as sand and gravel, subsiding at the bottom of the sea, and having their interstices filled with water, possess a kind of fluidity; they are disposed to yield on the side opposite to that where the pressure is greatest, and are, therefore, in some degree, subject to the laws of hydrostatics. account they will arrange themselves in horizontal layers; and the vibrations of the incumbent fluid, by impressing a slight motion backward and forward, on the materials of these layers, will very much assist the accuracy of their level. Now rocks, having their layers exactly parallel, are very common, and prove, their original horizontality to have been more precise than we could venture to conclude from analogy alone. In beds of sandstone, for instance, nothing is more frequent than to see the thin layers of sand, separated from one another by layers still finer of coaly, or micaceous matter, that are almost exactly parallel, and continue so to a great extent without any sensible deviation. These planes can have acquired their parallelism only in consequence of the property of water just stated, by which it renders the surfaces of the layers, which it deposits, parallel to its own surface, and, therefore, parallel to one another. Though such strata, therefore, may not now be horizontal, they must have been so originally; otherwise it is impossible to discover any cause for their parallelism, or any rule by which it can |