masses, which in other countries spread over a large surface, or are raised into lofty chains of mountains. Thus, commencing at the eastern coast,―at the German ocean, in Essex, and traversing England in a north-westerly direction, we pass over the whole series, from what are regarded as the most recent, to the most ancient depositions, and, with few exceptions, find each in the place assigned to it in the order of succession, corresponding with the order in which they are piled upon each other in the continent of Europe. One or two beds, the muschelkalk and the rothe-liegende of the Germans, which in the north of Germany are considerable formations interposed between our new red sandstone and the coalformation, were generally supposed to be absent in this country; but Professor Sedgwick has lately discovered their corresponding types in the English series, so that the analogy is now complete. These various beds, as I have before stated, are identified by means of the organic fossils peculiar to each, and by the aid of these, geologists have arranged them into groups, having reference to the epochs of their formation-a sort of Zodiacal system, which enables us to measure, as it were, the lapse

of

ages, and to fix upon determinate points in the immensity of time which our inquiries involve, as those celebrated signs aid the astronomer, in determining the position of the innumerable stars which glitter in the vast expanse of the heavens.

In the arrangement at present adopted, it is customary to class all the phenomena of stratified and unstratified rocks, into four grand divisions, which comprise all the minor subdivisions; and the terms adopted are supposed to express something like the relative ages

of each. These generic terms are the primitive, transition, secondary, and tertiary, and it is usual to commence with the primitive or most ancient rocks, and come down to the most recent, as historians begin with remote, and come down to contemporary times. I shall invert the process, going back in the series from the newest to the oldest-from contemporaneous to remote periods-and shall only make use of the terms where they are essential in fixing the brief outlines of my sketch.

But before we examine the older strata, the stratified masses comprised in the arrangements above adverted to, which contain, as it were, the records of remote periods, we must examine the changes now taking place on the earth's surface, the events of what may be termed the contemporaneous period-changes which have affected the destiny of man-the effect of causes now in operation.

These are the action of rivers, and their deposits; the destructive and reproducing effects of the ocean; the amazing agency of volcanos and earthquakes; the accumulation of peat-bogs, and the growth of coral reefs; to the incessant and long-continued action of which causes, Mr. Lyell refers all the changes which the earth's surface has experienced-a theory which it is the special object of his three interesting volumes to prove.*

None of these changes can be appreciated in this part of the world, where all the disturbing forces are quiet, earthquakes rare events, and volcanic agency unknown; and where the physical features of the coun

The undue attachment to a favorite theory which pervades these volumes greatly impairs their value and general interest.

try are on so small a scale. It is in the great continents, the seat of active volcanos, that their effects are sensibly felt. Thus the great river Mississippi, in America, has frequently filled up its bed, and furrowed out channels in a new direction, and is fast filling up the Gulph of Mexico with the prodigious amount of solid matter brought down in its course. Enormous masses of timber and vegetable matter, swept by the flood from the primeval forests of that vast country, sometimes block up the channel of its tributary streams, as in the Red river, where a raft, or an accumulation of timber and vegetable matter, is formed, twenty miles in length, of great width, and many feet in thickness: in other places the torrent is undermining its banks, while lakes and islands are forming at its æstuary. As with the Mississippi, so with other large rivers—the Ganges, the Indus, the Niger, the Nile, and the European rivers. Such is the vast accumulation of matter at the efflux of the Niger to the Atlantic, that its course has been with difficulty ascertained; this mighty stream, in fact, is buried in its own sands, which have stolen from the Atlantic a space equal to the whole surface of England. In Europe, upon a smaller scale, there are the delta* of the Rhone in the Mediterranean, where a considerable tract of land has gained upon the sea,† and the flat land at the mouth

* At the efflux of a river into the ocean its volume expands and its banks spread out angularly in the form of the Greek letter A; hence the origin of the term delta.

A large extent of the delta of the Rhone is known to have accumulated since the time of the Romans, and to have assumed the form of solid rock even within a later period; inasmuch as a

of the Rhine-the whole country of Holland in factwhich has been raised from the German ocean, by the accumulation of matter brought down by this mighty stream. On the other hand, however, the sea, resenting this encroachment, has exhibited manifest symptoms of reaction; and at " one fell swoop" it reclaimed fifty thousand acres! forming that large inland bay upon which Amsterdam is built-the Zuider Zee; and it requires all the industry of the Dutch to prevent the

cannon imbedded in a crystalline limestone rock has been taken from the bed of that river. Sir Richard Phillips states in his "Million of Facts" that to consolidate a soft substance into a hard rock requires at least 4000 years! If his "Facts" had been more select, and less numerous, his work would not have been the less valuable.

* An idea may be formed, of the geological effect of rivers, from the experiments of Mr. Horner, upon the waters of the Rhine, detailed in a recent communication to the Geological Society. From these experiments, which were conducted with great care, it appears that earthy matter constitutes from one-twelfth to onetwentieth (varying with the season,) of the whole bulk of the water of this celebrated river. At Bonn, where the observations were made, the width of the river is twelve hundred feet, the mean depth fifteen feet, and the mean velocity of the current two and a half miles per hour: the average quantity of earthy matter held in suspension in the water having been ascertained to be twenty-eight grains in the cubic foot, the extraordinary result is obtained, that one hundred and forty-five thousand nine hundred aud eighty-one cubic feet of solid matter is borne past Bonn every twenty-four hours, on its voyage from the Alps to the German ocean. No wonder that the Rhine should lose its identity as it approaches the termination of its course, and that it should contract into the dimensions of an ordinary canal. But the Rhine at Bonn, is a pellucid stream, compared with the Rhone at Lyons, in the summer

season.

recurrence of similar depredations. As if to assert its supremacy, its ordinary tides now rise above the level of the country, and its infuriated billows continually menace with destruction the floodgates and barriers opposed to their progress.

Every river, and every æstuary, present us with similar phenomena, and the aggregation of matter thus formed, and forming, is generally termed alluvium, in contradistinction to diluvium, which is applied to the effects supposed to have resulted from the deluge. The flat land on each side of the river Forth, in Scotland, is an instance where the currents and tides have combined, by their reciprocal action, to form alluvial beds. In the gravel and other matter thus thrown up, vestiges of the causes by which they were produced of course are found; on the one hand wrecks of the ocean, on the other ruins of the land are simultaneously gathered together in the same heap; thus in the alluvial gravel alluded to, the skeleton of an enormous whale has been discovered, and other relics of the ocean, intermixed with the rocky fragments brought down from the neighbouring mountains.

But the changes in the earth's surface produced by the action of rivers, are exceedingly slow, and in magnitude insignificant, compared with those which it is more particularly the business of Geology to investigate. Thus the Nile, a river of which we have the earliest and most authentic records, although its stream, densely charged with solid matter, annually overflows the plains of Egypt, has only raised the level of the surface which it inundates, six feet four inches since the commencement of the Christian æra, and the accumulation