tion, and the toad must have been full grown at the time. Toads are often found in compact, hard, gravelly diluvial deposits, in situations which demonstrate that they must have lived from the time of the deluge. I think I am warranted in saying this without citing authorities, as it is a common occurrence. Then why may they not have lived a few centuries longer, if we admit them a life of at least three thousand years?'

GENERAL REMARKS ON GEOLOGY.

Geological researches are made with much greater facility in America than in Eu rope, especially in the region of the secondary strata. The immense extent over which they can be traced, the undisturbed condition in which they are found, and their generally horizontal position, afford great facility for efforts of system and generalization The absence of the newest floetz-trap rocks, and of the effects of the violent convulsions. so frequent in the vicinity of this disputed formation, unquestionably assist geological research. A second and more efficient cause is found in the extent of the changes that have been wrought in the different classes of rocks on the European continent since their original formation, by the effect of water, and the continual action of rivers wearing deep beds, and exposing the subordinate strata. Rivers also in North America have not generally cut so deep into the different strata, either in the mountains, or during their course in the level country, as materially to derange the stratifications. Broken masses of one formation covering the tops of mountains, whose foundations are composed of rocks of a different class, seldom occur. A third cause of the facility of geological observation in this continent is found in the fact that the whole continent east of the Mississippi follows the arrangement of one great chain of mountains. Europe, on the contrary, is intersected by five or six distinct ranges, which follow different laws of stratification, and frequently interrupt each other.

The effect of opening this new field of observation has been striking and important. It has been to confound every previous effort at the determination and arrangement of general strata. European geologists themselves have acknowledged that the general strata must be determined in America. The absence of the chalk forcibly illustrates this; the chalk being not only a very prominent feature in the geological structure of Europe, but the grand point of division between the secondary and tertiary formations. The English oolite is not found in this country. It has been affirmed by Professor Eaton that the old red sandstone is not a general stratum, and even the existence of primitive clay-slate is questioned; while Mr. Maclure informs us that though the primitive formation contains all the variety of rocks contained in the mountains of Europe, yet neither their relative situation in the order of succession, nor their relative heights in the range of mountains, correspond with European observations. The order of suc cession from the clay-slate to the granite, as well as the gradually diminishing height of the strata, from the granite through the gneiss, mica slate, and hornblende rock, down to the clay-slate, is so often inverted and mixed, as to render the arrangement of any regular series impracticable.

It is of course out of the question in these remarks to present a detailed account of the general science of geology. For valuable and well-digested treatises on this subject, we refer to Cuvier's Theory of the Earth, and Lyell's Principles of Geology. The volumes of Silliman's Journal, and Professor Cleaveland's works, abound in important matter on the geology of our continent.

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CHAPTER XIX.-NATURAL CURIOSITIES.

Ir is our intention to collect under this general head a few miscellaneous descriptions, that could not have been properly placed under any other division. The space that we can devote to this subject is small, and it is impossible to enter into much detail. Among the most admired and interesting natural curiosities of our country, are the Pictured Rocks, of lake Superior, which have been described by an intelligent traveller to whose observation we have been already largely indebted.

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'The Pictured Rocks,' says Mr. Schoolcraft, are a series of lofty bluffs, which continue for twelve miles along the shore, and present some of the

most sublime and commanding views in nature. We had been told, by our Canadian guide, of the variety in the color and form of these rocks, but were wholly unprepared to encounter the surprising groups of overhanging precipices, towering walls, caverns, waterfalls, and prostrate ruins, which are here mingled in the most wonderful disorder, and burst upon the view in ever-varying and pleasing succession. In order to convey any just idea of their magnificence, it is necessary to premise, that this part of the shore consists of a sandstone rock of a light gray color internally, and deposited stratum super-stratum to the height of three hundred feet, rising in a perpendicular wall from the water and extending from four to five leagues in length.

This rock is made up of coarse grains of sand, united by a calcareous cement, and occasionally imbedding pebbles of quartz and other waterworn fragtents of rocks, but adhering with a feeble force, and, where exposed to ae weather, easily crushed between the fingers. Externally, it presents a great variety of color, as black, red, yellow, brown, and white,

22*

particularly along the most permanent parts of the shore; but where masses have newly fallen, its color is a light gray. This stupendous wall of rock, exposed to the fury of the waves, which are driven up by every north wind across the whole width of lake Superior, has been partially prostrated at several points, and worn out into numerous bays and irregular indentations. All these front upon the lake, in a line of aspiring promontories, which, at a distance, present the terrible array of dilapidated battlements and desolate towers.

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Among many striking features, two attracted particular admiration,the Cascade La Portaille, and the Doric Arch. The cascade is situated about four miles beyond the commencement of the range of bluffs, and in the centre of the most commanding part of it. It consists of a handsome stream, which is precipitated about seventy feet from the bluff into the lake at one leap. Its form is that of a rainbow, rising from the lake, to the top of the precipice. We passed near the point of its fall upon the surface of the lake, and could have gone, unwetted, between it and the rocks, as it is thrown a considerable distance into the lake.

The Doric Rock is an isolated mass of sandstone, consisting of four natural pillars, supporting a stratum or entablature of the same material, and presenting the appearance of a work of art. On the top of this er tablature rests a stratum of alluvial soil, covered with a handsome growth of pine and spruce trees, some of which appear to be fifty or sixty feet in height. To add to the factitious appearance of the scene, that part of the entablature included between the pillars is excavated in the form of a common arch, giving it very much the appearance of a vaulted passage inte the court yard of some massy pile of antiquated buildings. A little to the west of this rock, the Miner's river enters the lake by a winding channel, overshadowed with trees, and intersected by a succession of small rapids. Mineralized Tree.-About half a mile from the village of Chitteningo, in New York, a fossil or mineralized tree was some years ago discovered. It lies at the base of the Conasewago mountains, within a few yards of a branch of the Erie canal, which runs up to the village. The tree appears to have been blown down or broken off; there are eight or ten feet of stump remaining, with some part of the large end near the root; the stump is about three feet in diameter, the bark, the fibrous texture of the wood and two or three knots are very obvious; there is a substance very much resembling veins disseminated through what seems to have once been the sap vessels of the tree. The lower part of the root is imbedded in the soil, where it probably once grew. Vast quantities of mineralized wood, both in small and large masses, are scattered in all directions around this stump; fragments which from their loose and porous texture, seem to have been petrified, after the wood began to decay. Indeed so numerous are these fragments, that almost every stone in this vicinity appears to have been once a living plant.*

The Devil's Diving Hole.-About four miles below the falls of Niagara. on the American side, is a very curious place called the Devil's Diving Hole, which is nearly one hundred feet deep; the edge of it is so very near the road that they have taken the precaution to cut down some trees, so as to form a kind of barricado, in order to prevent cattle or strangers from

*Silliman's Journal.

falling into it. This hole, as it is called, is, more properly speaking, the narrow extremity of a considerable ravine, which has, at some remote period, been formed in the rock; it shelves off as it descends towards the river, and is in length about two hundred yards from the road to the river. The top is so overgrown with bushes that a hasty view would induce many to suppose it to be really a hole; but a closer examination soon leads their eye along the windings of its courses, and discovers a very considerable breadth at no great distance. A hemlock tree, firmly rooted at the bottom, stretches its top almost to the surface, and is so conveniently fitted to the hole or opening, that you have only to descend five or six feet, when its branches afford you a safe and easy step-ladder quite to the bottom, where you will find a copious spring of excellent water.

An occurrence is traditionally described as having taken place at this spot during the French war, the circumstances of which were as follows:A British detachment, being pursued by a superior French force, were so hemmed in that their retreat to the road was cut off, and their escape effectually prevented by this ravine. Seeing their situation irretrievable, they laid down their arms, and surrendered themselves prisoners of war. Notwithstanding this surrender, the French rushed upon them with charged bayonets and precipitated the whole party down this precipice. Here they perished with the exception of a single soldier, who was preserved by falling on some of his comrades.

Natural Bridge.-This wonderful bridge is considered by many the greatest natural curiosity in this country. It has never been described so well as by Mr. Jefferson, and though his account of it has been so frequently reprinted, we have thought best to adopt it.

The Natural Bridge, the most sublime of nature's works, is on the ascent of a hill, which seems to have been cloven through its length by some great convulsion. The fissure just at the bridge is by some admeasurements two hundred and seventy feet deep, by others only two hundred and five. It is about forty-five feet wide at the bottom, and ninety feet at the top this of course determines the length of the bridge and its height from the water. Its breadth in the middle is about sixty feet, but more at the ends, and the thickness of the mass at the summit of the arch, about forty feet. A part of this thickness is constituted by a coat of earth, which gives growth to many large trees. The residue, with the hill on both sides, is one solid rock of limestone.

The arch approaches the semi-elliptical form, but the larger axis of the ellipsis, which would be the chord of the arch, is many times longer than the transverse. Though the sides of this bridge are provided, in some parts, with a parapet of fixed rocks, yet few men have resolution to walk to them and look over into the abyss. You involuntarily fall on your hands and feet, creep to the parapet, and peep over it. Looking down from this height about a minute, gave me a violent headache.

If the view from the top be painful and intolerable, that from below is delightful in an equal extreme. It is impossible for the emotions arising out of the sublime to be felt beyond what they are here, so beautiful an arch, so elevated, so light, and springing, as it were, up to heaven, the rapture of the spectator is really indescribable!

The fissure continuing narrow, deep, and straight for a considerable distance above and below the bridge, opens a short but very pleasing view

of the North mountain on one side, and the Blue ridge on the other, at the distance each of them of about five miles. This bridge is in the county of Rockbridge, to which it has given name, and affords a public and commodious passage over a valley, which cannot be crossed elsewhere for a considerable distance. The stream passing under it is called Cedar creek. It is a water of James river, and sufficient in the driest seasons to turn a grist-mill, though its fountain is not more than two miles above.'

The description which follows is from another writer. 'As we stood under this beautiful arch, we saw the place where visitors have often taken the pains to engrave their names upon the rock. Here Washington climbed up twenty-five feet and carved his own name, where it still remains. Some wishing to immortalize their names have engraved them deep and large. while others have tried to climb up and insert them high in this book of fame.

'A few years since, a young man, being ambitious to place his name above all others, came very near losing his life in the attempt. After much fatigue, he climbed up as high as possible, but found that the person who had before occupied his place was taller than himself, and consequently had placed his name above his reach. But he was not thus to be discouraged. He opened a large jacknife, and in the soft limestone began to cut places for his hands and feet. With much patience and industry he worked his way upwards, and succeeded in carving his name higher than the most ambitious had done before him.

'He could now triumph; but his triumph was short, for he was placed in such a situation that it was impossible to descend unless he fell upon the ragged rocks beneath him. There was no house near, from which his companions could get assistance. He could not remain in that condition, and, what was worse, his friends were too much frightened to do any thing for his relief. They looked upon him as already dead, expecting every moment to see him precipitated upon the rocks below and dashed to pieces. Not so with himself. He determined to ascend. Accordingly he plied himself with his knife, cutting places for his hands and feet, and gradually ascended with incredible labor. He exerted every muscle. His life was at stake, and all the terrors of death rose before him. He dared not look downwards lest his head should become dizzy, and perhaps on this circumstance his life depended.

His companions stood at the top of the rock exhorting and encouraging him. His strength was almost exhausted; but a bare possibility of saving his life still remained, and hope, the last friend of the distressed, had not yet forsaken him. His course upwards was rather oblique, than perpendicular. His most critical moment had now arrived. He had ascended considerably more than two hundred feet, and had still further to rise, when he felt himself fast growing weak. He now made his last effort and succeeded. He had cut his way not far from two hundred and fifty feet from the water, in a course almost perpendicular; and in a little less than two hours, his anxious companions reached him a pole from the top, and drew him up. They received him with shouts of joy; but he himself was completely exhausted. He immediately fainted away on reach ing the spot, and it was some time before he could be recovered.

It was interesting to see the path up these awful rocks, and to follow in