the nations of the world? With regard to the first part of this objection, we have only to remark, that the gradual, and not instantaneous communication of revealed religion, may be accounted for on principles which ought to be admitted by every philosophical mind. It is demonstrated by the concurrent testimony of ancient, profane, and sacred history, that the world in its earlier existence was enveloped in the densest moral darkness-that it was in many respects, most materially different from what it is at the present moment;and, consequently, if the generations of the earlier stages of the world were in a state of comparative intellectual childhood, it must necessarily follow, that in proportioning the degree of supernatural revelation, to men's capacities to receive it, the Divine Being was acting consistently with infinite wisdom. It ought to be enough for us, to recollect, that though Jehovah had resolved on blessing the world with a special revelation of his will, he surely could reserve to himself the right of communicating it in any manner consistent with his sovereign pleasure.

In answer to that part of the objection against the credibility of Christianity from the circumstance of its not being universal, it may in the first place be observed, that it is not the province of erring mortals to scan the oftentimes mysterious purposes and dispensations of Him who is infinite in counsel and excellent in working. His ways are frequently in the sea, and his paths in the great deep. But although the course of his moral procedure oft-times baffles our profoundest attempts to comprehend it, this constitutes no admissible reason why we should deny or doubt that moral procedure in one single instance; for if such a principle were traced to legitimate consequences, it would effectually exclude the Divine agency from the world altogether. In contemplating the economy either of creation or of providence, we meet with innumerable circumstances which are perfectly inexplicable to us. We cannot, for example, perceive what particular purpose the Deity can have to answer in the creation of such an extensive desart as Zaara, in which neither man nor beast is capable of existing nor can we conceive why he should visit with precious showers, many extended tracts of country in our land, which are incapable of vegetation:yet the formation of the desart, and the communication of rain to our earth, are works which the deist unites with the Christian in ascribing wholly to the agency of the Supreme Being.

Let it, however, only be impressed on the mind, that the present is a probationary state, and the difficulties which have been supposed to result from the circumstance of the Christian revelation not being universal, will utterly vanish. The Divine Being usually works by human instrumentality; and while he enjoins on all who enjoy the blessings of Christianity, the duty of exerting themselves to the utmost of their power to transmit its benefits to such of their fellow-men as may be destitute of them,-it must be at their peril if they are unfaithful to the important trust which he has confided in them. It is anxiously to be wished that the professed followers of Jesus were more profoundly impressed with a conviction of the fearful responsibility which in this respect attaches to the favourable spiritual circumstances in which they are situated; and we feel no hesitation in avowing it as our decided opinion, that had the past and present professors of Christianity done their duty in the propagation of the gospel, there would not at this moment have been one single individual destitute of its external privileges.

But whatever may be thought of the preceding observations, it cannot be denied that the objection is equally formidable against natural religion. It is a fact indelibly recorded in the history of the present, as well as the past condition of the world, that there are individuals whose mental and physical circumstances in regard of natural religion, are incomparably more unfavourable than those of others. "In contemplating the dispensations of Divine Providence, we clearly perceive that God has made very material distinctions between the measure of wisdom, understanding, and other intellectual advantages, which he has bestowed upon one individual, and those he has bestowed upon another. Yet the disproportion which exists betwixt the mental capacities of one, and those of another, is never adduced as a reason why we should question the agency of the divine Being in the bestowment of them in either case. And as it is with individuals in one country, so is it with nations in general. Will any of the deists of the present day have the consummate audacity to maintain, that the inhabitants of Kamtschatka, or the negroes of Africa, are placed in equally advantageous circumstances regarding natural religion, as the natives of Britain, or the population of the United States of America? If not, the Christian has a vantage-ground, from which he may effectually repel those objections which in

COMPENDIUM OF GEOLOGY.--NO. VII.

A COAL-FIELD is frequently succeeded by a stratum of magnesian lime-stone, bearing the name of dolomite: this stratum is of immense magnitude, and rises in bold escarpments to great heights into the atmosphere: huge precipices and vast rocks frequently occur therein, which form the most picturesque scenery, over the face of a district several miles broad, and scores of miles in length. The crystals of which this rock is composed are generally fine, and somewhat resemble those of statuary marble; but wherever a cement exists, by which they are united, it is not quite so firm; hence, excepting some choice specimens, this stone is neither so tenacious nor endurable as statuary marble; but where the blocks in quarrying are well selected, the difference is not so obvious. The fact is, that almost every stratum of stone contains several beds or seams in the same rock, and from any or all these seams the quarry-men work such blocks as they perceive are solid, and turn them out for sale but the only good property in a rock is not solidity at the time it is quarried; an essentially good property is endurance, or solidity in continuance, when exposed to the action of the atmosphere, amidst the storms and heats of revolving seasons. Some blocks from the rocks will endure like time itself; whereas others, although solid when quarried, shiver on exposure in a single season, or in two or three seasons, crumble, so as appear incessantly covered with rust or dust; and in process of time these stones moulder away.

The debris of this rock does not invariably afford a rich soil, although the product thereof, viz. lime, is a fertilizing manure. The fact is, the crags from these rocks frequently project through the soil, and lie exposed for ages in an undecomposed state; and the soil itself between these crags is often thin, and mixed up with small fragments of the crags themselves, which, like the parent rock, brave the efforts of time. In some situations, especially where a mixture of ferruginous clay occurs, the

soil is fertile to a proverb; and I have no doubt ferruginous clay from the coal-field near at hand, where it exists to redundancy, if treated with a slight calcination, would act as an excellent manure upon the thin and craggy portions of this soil.

Carbonic acid, in nearly the proportion of half the substance, lime, in the proportion of a full third, and magnesia, in nearly the proportion of one-fifth, constitute the magnesian lime-stone stratum. On ferruginous soils, lime from this rock is an excellent manure. Not being so quick in its processes upon the soil as the mountain lime, owing to the magnesia with which it is charged, the effects of this lime upon several soils are not so soon produced as those from purer lime; but it possesses a virtue which more than counterbalances this defect, viz. that of endurance; for if the effects of this lime do not so quickly follow its application as a manure, they continue longer.

Calcareous sand-stone rocks occur in the immediate vicinity of the dolomite, and frequently alternate therewith; and these strata, by insensible gradations, run into each other. The crystals of these calcareous rocks are minute, and the cement, in some specimens, is firm and endurable. A beau tiful white colour pervades these specimens, and they are quarried large and firm for building and ornamental uses; and these blocks, when well chosen, rank with the first-rate stones. The name of freestone is aptly enough applied to this rock, from the great freedom and precision with which it is wrought; and the beauty of the finest specimens beneath the chisel of the statuary gives it a high character in ornamental architecture. Minute mosses, the seeds of which are often carried aloft by strong winds, frequently take root in and vegetate upon the surfaces of this stone, which give it a greenish hue; and the magnesia contained in its structure will sometimes induce the same colour upon the surface. This green appearance deducts from its beauty and value; but the remedy is easy; and the only wonder in this case is, that it is not universally applied.

To the dolomite frequently succeeds a massive sand-stone stratum, which occasionally towers in vast rocks, and terminates in high precipitous escarpments above, and descends to great depths beneath the surface of the earth. The crystals of which these rocks are composed are of a mixed character; but the siliceous have precedence over all the rest. In some specimens the crystals are large, and protrude boldly from thec ement; while in others they are smaller, and in some as fine as the finest sand,

The cement which unites these crystals is composed of oxide of iron and clay in various proportions; where the proportion of iron is large, the rock is firm, where it is small, the rock is tender; and in many specimens it is so friable that it moulders to sand.

The coal strata extend their inclined planes beneath the dolomite or magnesian limestone. In several instances mines have been sunk through the dolomite into the coal strata, and the coal there worked. In these situations the coal strata have been found as sound and good as in any other portion of a coal-field. There are even instances of coal strata becoming visible, in deep ravines, beyond the extent of the dolomite's place upon the earth's surface, and beneath the calcareous sandstone strata which succeed that stratum. The calcareous strata which succeed the dolomite extend beneath the adjoining sand-stone stratum; and as the coal strata are perfect beneath these calcareous strata before they descend beneath the sandstone, why not afterwards? I see no more reason to doubt the existence of the coal strata, perfect and entire beneath the sand. stone stratum, than beneath the dolomite : the only difference in this case is, the latter has been demonstrated; we rest upon it, therefore, as a fact; but the former, perhaps has not; I say perhaps, because speaking solely from my own knowledge, this, as a fact, has not been demonstrated to me, although it may be equally familiar with other facts to other persons.

The escarpments of the dolomite receive, in copious quantities, a fresh supply of water from the atmosphere, and faithfully transmit this to the argillaceous strata of the coal-field below; and this circumstance applies also to the calcareous strata and the sand-rocks which succeed; beneath so much extra cover, therefore, the coal is preserved in all its primitive richness for the last ages of time. It is a fact, observable in coal-fields, that the upper portions of the inclined strata of coal are first worked; because the extra expense attendant on sinking shafts, draining the mine, and drawing up the coal from the lower parts of the same plane, cannot be borne until the higher portions of the plane are exhausted; and this applies also to the upper beds or strata of coal, in preference to the deep strata. This circumstance is favourable to the preservation of coal for after-ages; because that portion of the coal which was only slightly covered, and in danger of being injured by continuing in a state of partial exposure, is first in use,

while that which is protected by vast and solid superstrata is retained thus pure for futurity. How admirable are the works of Jehovah !

The coal strata beneath the dolomite, the calcareous sand-stone, and, doubt not, the sand-rocks and succeeding strata, having such immense additional covering, are more indurated, and of course more firm in their texture, and are of superior quality to the coal in the higher portions of the coal-field indeed, in general, in proportion as coal strata are worked at greater depths beneath the earth's surface, they are found to be superior in quality to those worked near the surface. Thus does the prescience and providence of the Infinite reserve the best for the last. How different this to the improvident prodigality

of man!

These circumstances open to our view a wider extent of coal strata than the limited views of some writers upon this subject admit; and I have no doubt that many estates situate upon the deep of coalfields will in time become exceedingly valuable, while those upon the upper grounds will have comparatively dwindled in value, from the circumstance of the coals being exhausted therein. That gloom which the prodigal manners of the present age, which is busied in tearing up the coal from the bowels of the earth, and dissipating it in every possible way, as if they supposed a coal stratum reproduced and increased itself, similar to corn in the field, the gloom, I say, which this prodigal age has cast, like a dense cloud, over the minds of all who have felt themselves identified with posterity, and reflected that Jehovah created this sphere for every age of man, and not for one only, is in part dissipated by the enlargement of the coal-field; inas. much as it removes the evil which the want of coal must one day inflict upon the world to a more distant period: but although it dissipates this gloom for the moment, this circumstance does by no means eradicate it, and restore serenity to a thinking mind which carries its views into distant futurity.

It is a fact well known, that coal does not exist beneath certain portions of the surface of this sphere; and these portions are, collectively, of far greater extent than those under which there is any chance of the existence of coal; and beneath those portions of the earth's surface where the mere chance of finding coal strata presents itself, the probability is, that not one half of these will ever yield a single ton of coals for the use of man. The supply,

where the character is well defined, and admits of the least degree of obscurity and doubt. Those that occupy the intermediate stations may then have their correspondent types pointed out; the less definite nature of their character being in fact that whereby they are to be rendered distinct.

Among quadrupeds a very distinguished place is assigned to the feline race, at the head of which stand the lion and tiger; whose corporal characters are the peculiar form and arrangement of their teeth, adapted for seizing and tearing their prey; -and the retractile claws, that prove such formidable weapons of offence. From these, as from a central type, diverge the species of which this genus consists; until it becomes a matter of doubt whether certain of them should be arranged in this or another genus.

Passing from quadrupeds to birds, we there perceive a class that has nothing in its bodily structure which bears an affinity to that we have just been speaking of; yet it must be acknowledged that there is in their characters a very close analogy. The same solitary, bold, predaceous habits, the same disposition for blood and slaughter, form a correspondency that cannot be mistaken.

Proceeding to the inhabitants of the ocean, there is none, however unskilled in natural history, who would not point out the shark as occupying among fish the same station as the eagle among birds, and the tiger among quadrupeds; and when we are become better acquainted with the insect and serpent tribes, there is no question that we shall find correspondent analogies in these departments of nature also. If the opinion of a gnat were taken, it is probable that the dragon-fly would be pronounced the most ferocious creature in existence. The chimæra bears the same similarity of form to the shark, and exhibits the same dissimilarity of habits, as the parrot does to the eagle; while the dove and the sheep possess a similar placidity of character, that lays them open to every violence.

In the present state, of our knowledge, it would be a task of great difficulty to trace these natural analogies in all the principal groups of creatures, for a correct knowledge of their habits is a necessary qualification; and unfortunately in several orders these have had but little attention directed to them. But to guide those who may be disposed to pursue the inquiry, it should be remarked, that as the Almighty Author of nature is uniform

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in his works, we are justified in supposing that the analogical groups will be found to bear the same relationship of form to those to which they bear an affinity, in all the grand divisions of the kingdoms of nature. Thus, if the lion, the eagle, and the shark, possess an analogy of natural character, those creatures which have a natural affinity (from similarity of figure) with the lion, the eagle, and the shark, should find their correspondent analogies of character in those genera that come the nearest to the genera of which these creatures respectively form the types.

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So, on one side of the eagle stands the vulture, on another the parrot, each nearly related in natural affinity, yet sufficiently distinct to form separate groups of themselves. Correspondent to this, on side of the shark is the chimæra, answering to the parrot; on the other the skate, having an analogy to the vulture. We here perceive the same affinity to the creature selected as the type, and the same analogy to its correspondencies.

This view of a subject, exceedingly curious in itself, is further illustrated by reference to some groups of creatures that seem to stand out in prominent relief, from the natural associations by which they are surrounded. Thus, not only, as we have seen, does each class of animated beings contain certain prominent families of distinct character, that find their correspondent analogies in the other classes; but we find the classes themselves united and brought into a whole, in a similar manner, by certain natural affinities of form and structure that link them together; which again have their natural analogies, separate and distinct from any correspondency of form. Of the former, or affinity of form and structure binding the separate orders together, we have an example in the duck-billed animal (ornithorhynchus paradoxus;) whose habits are those of a quadruped, but whose structure partakes as much of the bird as the beast; and also in the manatee, that unites the quadruped in close affinity to the fish. In the creatures, however, in which the analogies are very strongly marked, as if to point out the complete distinction between that and affinity, no correspondency of form is suffered to exist, however much it may seem to be required. For while the whale has all the habits of a fish, its parts are those of a quadruped, and it has nothing similar to gills; but is compelled to breathe the air, though at the risk of its life; while the flying-fish, that often quits the water