THE

HISTORY AND THEORY

OF THE

EARTH.

THE figure of the earth,* its motions, or the external relations which subsist between it and the other parts of the universe, belong not to our present inquiry.  It is the internal structure of the globe, its form and manner of existence, that we here propose to examine.  The general history of the earth ought to precede that of its productions. Details of particular facts relating to the oeconomy and manners of animals, or to the culture and vegetation of plants, are not, perhaps, so much the objects of natural history, as general deductions from the observations that have been made upon the different materials of which the earth itself is composed; as its heights, depths, and inequalities; the motions of the sea, the direction of mountains, the situation of rocks and quarries, the rapidity and effects of currents in the ocean, &c. [1]  This is the history of nature at large, and of her principal operations, by which every other inferior or less general effect is produced.  The theory of these effects constitutes what may be called the primary science, upon which a precise knowledge of particular appearances, as well as of terrestrial substances, solely depends.  This species of science may be considered as appertaining to physics; but, is not all physical knowledge, where system is excluded, a part of the history of nature.

            In subjects of an extensive kind, the relations of which it is difficult to trace, where some facts are but partially known, and others obscure, it is more easy to form a fanciful system, than to establish a rational theory.  Thus the theory of the earth has never hitherto been treated but in a vague and hypothetical manner.  I shall, therefore, exhibit only a cursory view of the notions of some authors who have written upon this subject.

            The first hypothesis I shall mention is more conspicuous for its ingenuity than solidity.  It is the production of an English astronomer, who was an enthusiastic admirer of Sir Isaac Newton’s system of philosophy.  Convinced that every possible event depends upon the motions and direction of the stars, he endeavours to prove, by means of mathematical calculations, [2] that all the changes this earth has undergone have been produced by the tail of a comet.

            For another hypothesis we are indebted to a heterodox divine,* whose brain was so fully impregnated with poetical illusions, that he imagined he had seen the universe created.  After telling us the state of the earth when it first sprung from nothing, what changes have been introduced by the deluge, what the earth has been, and what it now is, he assumes the prophetic style, and predicts what will be its condition after the destruction of the human kind.

            A third writer,⁺ a man of more extensive observation than the two former, but equally crude and confused in his ideas, explains the principal appearances of the globe by the aid of an immense abyss in the bowels of the earth; which, in his estimation, is nothing but a thin crust inclosing this vast ocean of fluid matter.

            These unstable hypotheses are all constructed on tottering foundations.  The ideas they contain are indistinct, the facts are confounded, and the whole is a motely [sic] jumble of physics and fable.  They, accordingly, have never been adopted but by people who embrace opinions without examination, and who, incapable of distinguishing the degrees of probability, are more deeply impressed with marvelous chimeras than with the force of truth.  [3]

            Our ideas on this subject will be less extraordinary, and may appear unimportant when compared with the grand systems just mentioned.  But it ought not to be forgotten, that it is the business of an historian to describe, not to invent; that no gratuitous suppositions are to be admitted in subjects that depend upon fact and observation; and that, in historical compositions, the imagination cannot be employed, unless for the purpose of combining observations, of rendering facts more general, and of forming a connected whole, which presents to the mind clear ideas, and probable conjectures:  I say, probable; for it is impossible to give demonstrative evidence on this subject.  Demonstration is confined to the mathematical sciences.  Our knowledge in physics and natural history depends entirely on experience, and is limited to the method of reasoning by induction.

            With regard to the history of the earth, therefore, we shall begin with such facts as have been universally acknowledged in all ages, not omitting those additional truths that have fallen within our own observation.

            The surface of this immense globe exhibits to our observation heights, depths, plains, seas, marshes, rivers, caverns, gulfs, volcano’s; and, on a cursory view, we can discover, in the disposition of these objects, neither order nor regularity.  If we penetrate into the bowels of the earth, we find metals, minerals, stones, bitumens, [4] sands, earths, waters, and matter of every kind, placed as it were by mere accident, and without any apparent design.  Upon a nearer and more attentive inspection, we discover sunk mountains,* caverns filled up, shattered rocks, whole countries swallowed up, new islands emerged from the ocean, heavy substances placed above light ones, hard bodies inclosed within soft bodies; in a word, we find matter in every form, dry and humid, warm and cold, solid and brittle, blended in a chaos of confusion, which can be compared to nothing but a heap of rubbish, or the ruins of a world.

            These ruins, however, we inhabit with perfect security.  The different generations of men, of animals, and of plants, succeed one another without interruption:  The productions of the earth are sufficient for their sustenance; the motions of the sea, and the currents of the air, are regulated by fixed laws;⁺ the returns of the seasons are uniform, and the rigours of winter invariably give place to the verdure of the spring.  With regard to us, every thing has the appearance of order:  The earth, formerly a chaos, is now a tranquil, an harmonious, a delightful habitation, where all is animated and governed by such amazing displays of power and intelligence, [5] as fill us with admiration, and elevate our minds to the contemplation of the great Creator.

            But, let us not decide precipitantly concerning the irregularities on the surface of the earth, and the apparent disorder in its bowels:  We shall soon perceive the utility, and even the necessity of this arrangement.  With a little attention, we shall perhaps discover an order of which we had no conception, and general relations which cannot be apprehended by a slight examination.  Our knowledge, indeed, with regard to this subject, must always be limited.  We are entirely unacquainted with many parts of the surface of this globe,* and have but very partial ideas concerning the bottom of the ocean, which, in many places, has never been sounded.  We can only penetrate the rind of the earth.  The greatest caverns,⁺ the deepest mines,³ descent not above the 8^th-thousandth part of its diameter.  Our judgment is therefore confined to the upper stratum, or mere superficial part.  We know, indeed, that, bulk for bulk, the earth is four times heavier than the sun:  We likewise know the proportion its weight bears to that of the other planets.  But still this estimation is only relative. We have no standard.  Of the real weight of the materials we are so ignorant, that the internal part of the globe may be either [6] a void space, or it may be composed of matter a thousand times heavier than gold.  Neither is there any method of making farther discoveries on this subject.  It is even with difficulty that rational conjectures can be formed.*

            We must therefore confine ourselves to an accurate examination and description of the surface of the earth, and of such inconsiderable depths as we have been able to penetrate.  The first object which attracts the attention, is that immense body of water with which the greatest part of the globe is covered.  These waters occupy the lowest grounds; their surface is always level; and, notwithstanding their uniform tendency to equilibrium and rest, they are kept in perpetual agitation by a powerful agent,⁺ which counteracts their natural tranquility, which communicates to them a regular periodic motion, alternately elevating and depressing their waves, and which produces a concussion or vibration in the whole mass, even to the most profound depths.  This motion of the water is coeval with time, and will endure as long as the sun and moon, which are the causes of it. 

            In examining the bottom of the sea, we perceive it to be equally irregular as the surface of the dry land.³  We discover hills and valleys, plains and hollows, rocks and earths of every [7] kind:*  We discover, likewise, that islands are nothing but the summits of vast mountains, whose foundations are buried in the ocean;⁺ we find other mountains whose tops are nearly on a level with the surface of the water; and rapid current which run contrary to the general movement.³  These currents sometimes run in the same direction; at other times their motion is retrograde;⁴ but they never exceed their natural limits, which seem to be as immutable as those which bound the efforts of land-rivers.  On one hand, we meet with tempestuous regions, where the winds blow with irresistible fury, where the heavens and the ocean, equally convulsed, are mixed and confounded in the general shock; violent intestine motions, tumultuous swellings,⁵ water-spouts,⁶ and strange agitations, produced by volcano’s, whose mouths, though many fathoms below the surface, vomit forth torrents of fire, and push, even to the clouds, a thick vapour, composed of water, sulphur [sic], and bitumen; and dreadful gulphs or whirlpools,⁷ which seem to attract vessels for no other purpose than to swallow them up.  On the other hand, we discover vast regions of an [8] opposite nature, always smooth and calm, but equally dangerous to the mariner.*  Here the winds never exert their force; the nautical art is of no utility; the becalmed voyagers must remain immoveably fixed, till death relieve them from misery.  To conclude, directing our eyes toward the southern or northern extremities of the globe, we discover huge masses of ice,⁺ which, detaching themselves from the polar regions, advance, like floating mountains, to the temperate climates, where they dissolve and vanish from our view.³

            Besides these grand objects, the ocean presents us with myriads of animated beings, almost infinite in variety:  Some clothed in light scales, swim with amazing swiftness; others, loaded with thick shells, trail heavily along, leaving their traces in the sand:  To others nature has given fins resembling wings, with which they support themselves in the air, and fly before their enemies to considerable distances.  Lastly, the sea gives birth to other animals, that, totally deprived of motion, live and die immoveably fixed to the same rocks:  All, however, find abundance of food in this fluid element.  The bottom of the ocean, and the shelving sides of rocks, produce plentiful crops of plants of many different species; its soil is composed of sand, gravel, rocks, and shells; in someplaces, it is a fine clay, in others, a compart earth; and, in gene- [9] ral, the bottom of the sea has an exact resemblance to the dry land which we inhabit.

            Let us next take a view of the land: What prodigious differences take place in different climates?  What a variety of soils! What inequalities in the surface!   But, upon a more attentive observation, we shall perceive, that the great chains of mountains lie nearer the equator than the poles;* that, in the Old Continent, their direction is more from east to west than from south to north; and that, on the contrary, in the New Continent, they extend more from north to south than from east to west. But, what is still more remarkable, the figure and direction of these mountains, which have a most irregular appearance,⁺ correspond so wonderfully, that the prominent angles of one mountain are constantly opposite to the concave³ angles of the neighbouring mountain,⁴ and of equal dimensions, whether they be separated by an extensive plain, or a small valley.  I have further remarked, that opposite hills are always nearly of the same height; and that mountains generally occupy the middle of continents, islands, and promontories, dividing them by their greatest lengths.⁵  I have likewise traced the courses of the principal rivers, and find that their direction is nearly perpendicular to the sea-coasts into which they empty themselves; and that, during the [10] greatest of their courses, they follow the direction of the mountains from which their derive their origin.*  The sea-coasts are generally bordered with rocks of marble, and other hard stones, or rather with earth and sand accumulated by the waters of the sea, or brought down and deposited by rivers.  In opposite coasts, separated only by small arms of the sea, the different strata or beds of earth are of the same materials.⁺  I find that volcano’s never exist but in high mountains;³  that a great number of them are entirely extinguished; that some are connected to others by subterranean passages, and their eruptions not unfrequently [sic] happen at the same time.⁴  There are similar communications between certain lakes and seas.  Some rivers suddenly disappear,⁵ and seem to precipitate themselves into the bowels of the earth.  We likewise find certain mediterranean or inland seas, that constantly receive, from many and great rivers, prodigious quantities of water, without any augmentation of their bounds, probably discharging by subterraneous passages all those extraneous supplies.  It is likewise easy to distinguish lands which have been long inhabited, from those new countries where the earth appears in a rude state, where the rivers are full of cataracts, where the land is either nearly overflowed with water, or burnt up with drought, and where every place [11] capable of producing trees is totally covered with wood.

            Proceeding in our examination, we discover that the upper stratum of the earth is universally the same substance;* that this substance, from which all animals and vegetables derive their growth and nourishment, is nothing but a composition of the decayed parts of animal and vegetable bodies, reduced into such small particles that their former organic state is not distinguishable.  Penetrating a little deeper, we find the real earth, beds of sand, lime-stone, clay, shells, marble, gravel, chalk, &c.  These beds are always parallel to each other,⁺ and of the same thickness through their whole extent.  In neighbouring hills, beds or strata of the same materials are uniformly found at the same levels, though the hills be separated by deep and large valleys. Strata of every kind, even of the most solid rocks, are uniformly divided by perpendicular fissures.³  Shells, skeletons of fishes, marine plants, &c. are often found in the bowels of the earth, and on top of mountains,⁴ even at the greatest distances from the sea.  These shells, fishes, and plants, are exactly similar to thosewhich exist in the ocean.  Petrified shells are to be met with, almost every where, in prodigious quantities:  they are not only inclosed in rocks of marble and lime-stone, as [12] well as in earths and clays, but are actually incorporated and filled with the very substances in which they are inclosed.  In fine, I am convinced by repeated observations, that marbles, lime-stones, chalks, marles [sic], clays, sand, and almost all terrestrial substances, wherever situated, are full of shells and other spoils of the ocean.*

            Having enumerated these facts, let us try what conclusions can be drawn from them.

            The changes which the earth has undergone, during the last two or three thousand years, are inconsiderable, when compared with the great revolutions which must have taken place in those ages that immediately succeeded the creation.  For, as terrestrial substances could not acquire solidity but by the continued action of gravity, it is easy to demonstrate, that the surface of the earth was at first much softer than it is now; and, consequently, that the same causes which at present produce but slight, and almost imperceptible alterations during the course of many centuries, were then capable of producing very great revolutions in a few years.  It appears, indeed, to be an uncontravertible [sic] fact, that the dry land which we now inhabit, and even the summits of the highest mountains, were formerly covered with the waters of the sea; for shells, and other marine bodies, are [13] still found upon the very tops of mountains.  It likewise appears, that the waters of the sea have remained for a long track of years upon the surface of the earth; because, in many places, such immense banks of shells have been discovered, that it is impossible so great a multitude of animals could exist at the same time.  This circumstance seems likewise to prove, that, although the materials on the surface of the were then soft, and, of course, easily disunited, moved, and transported, by the waters; yet these transportations could not be suddenly effected.  They must have been gradual and successive, as sea-bodies are sometimes found more than 1000 feet below the surface.  Such a thickness of earth or of stone could not be accumulated in a short time.  Although it should be supposed, that, at the deluge, all the shells were transported from the bottom of the ocean, and deposited upon the dry land; yet, beside the difficulty of establishing this supposition, it is clear, that, as shells are found incorporated in marble, and in the rocks of the highest mountains, we must likewise suppose, that all these marbles and rocks were formed at the same time, and at the very instant when the deluge took place; and that, before this grant revolution, there were neither mountains, nor marbles, nor rocks, nor clays, nor matter of any kind similar to what we are now acquainted with, as they all, with few exceptions, contain shells, [14] and other productions of the ocean.  Beside, at the time of the universal deluge, the earth must have acquired a considerable degree of solidity, by the action of gravity for more than sixteen centuries.  During the short time the deluge lasted, it is, therefore, impossible, that the waters should have overturned and dissolved the whole surface of the earth, to the greatest depths that mankind have been able to penetrate.

            But, without insisting longer on this point, which shall afterwards be more fully canvassed, I shall confine myself to known and established facts.  It is certain, that the waters of the sea have, at some period or other, remained for a succession of ages upon what we now know to be dry land; and, consequently, that the vast continents of Asia, Europe, Africa, and America, were then the bottom of an immense ocean, replete with every thing which the present ocean produces.  It is likewise certain, that the different strata of the earth are horizontal, and parallel to each other.*  This parallel situation must, therefore, be owing to the operation of the waters, which have gradually accumulated the different materials, and given them the same position which water itself invariably assumes.  The horizontal position of strata is almost universal:  In plains, the strata are exactly horizontal.  It is only in the mountains that they are inclined to the horizon; because they have ori- [15] ginally been formed by sediments deposited upon an inclined base.  Now, I maintain, that these strata must have been gradually formed, and are not the effect of any sudden revolution; because nothing is more frequent than strata composed of heavy materials placed above light ones, which never could have happened, if, according to some authors, the whole had been blended and dissolved by the deluge, and afterwards precipitated.  On this supposition, every thing would have had a different aspect from what now appears. The heaviest bodies would have descended first, and every stratum would have had a situation corresponding to its specific gravity.   In this case, we should not have seen solid rocks or metals placed above light sand, nor clay under coal.

            Another circumstance demands our attention.  No other cause than the motion and sediments of water could possibly produce the regular position of the various strata of which the superficial part of this earth is composed. The highest mountains consist of parallel strata, as well as the lowest valleys.  Of course, the formation of mountains cannot be imputed to the shocks of earthquakes, or to the eruptions of volcano’s.  Such small eminences as have been raised by volcano’s or convulsions of the earth, instead of being composed of parallel strata, are mere masses of weighty materials, blended together in the [16] utmost confusion.*  But this parallel and horizontal position of strata must necessarily be the operation and constant cause.

            We are, therefore, obliged to conclude, from repeated and uncontrovertible facts and observations, that the dry and habitable part of the earth has remained for a long time under the waters of the sea, and must have undergone the same fluctuation and changes which are presently going on at the bottom of the ocean.  To discover, therefore, what has formerly happened to the dry land, let us examine what passes in the bottom of the sea; and we shall soon be enabled to make some rational conclusions with regard to the external figure, and internal constitution of the earth.

            The ocean, from the creation of the solar system, has been constantly subject to a regular flux and reflux.  This motion, which happens twice in twenty-four hours, is principally occasioned by the action of the moon, and is greater in the equatorial regions than in other climates.  The earth likewise performs a rapid motion on its axis, and, consequently, has a centrifugal force, which is also greatest at the equator.  This last circumstance, independent of actual observations, proves, that the earth is not a perfect sphere, but that it must be more elevated under the equator than at the poles.  From these two combined causes, the tides, and the motion [17] of the earth, it may be fairly concluded, that, although this globe had been originally a perfect sphere, its diurnal motion, and the ebbing and flowing of the tides, must necessarily, in a succession of time, have elevated the equatorial parts, by gradually carrying mud, earth, sand, shells, &c. from other climates, and depositing them at the equator.*  On this supposition, the greatest inequalities on the surface of the earth ought to be found, and, in fact, are found, in the neighbourhood of the equator.  Besides, as the alternate motion of the tides has been constant and regular since the existence of the world, is it not natural to think, that, at each tide, the water carries from one place to another a small quantity of matter, which falls to the bottom as sediment, and forms those horizontal and parallel strata that every where appear?  The motion of the waters, in the flux and reflux, being always horizontal, the matter transported by them must necessarily take the same parallel direction after it is deposited. 

            To this, it may be objected, that, as the flux is equal to, and regularly succeeded by the reflux, the two motions will balance each other; or, that the matter brought by the flux will be carried back by the reflux; and, consequently, that this cause of the formation of strata must be chimerical, as the bottom of the ocean can never be affected by a uniform alternate motion [18] of the waters; far less could this motion change its original structure, by creating heights, and other inequalities. 

            But, in the first place, the alternate motion of the waters is by no means equal; for the sea has a continual motion from east to west: Beside, the agitations occasioned by the winds, produce great inequalities in the tides.  It will likewise be acknowledged, that, by every motion in the sea, particles of earth, and other materials, must be carried from one place, and deposited in another; and that these collections of matter must assume the form of parallel and horizontal strata. Farther, a well known fact will entirely obviate this objection.  On all coasts, where the ebbing and flowing are discernible,* numberless materials are brought in by the flux, which are not carried back by the reflux.  The sea gradually increases on some places, and recedes from others, narrowing its limits, by depositing earth, sand, shells, &c. which naturally take a horizontal position.  These materials, when accumulated and elevated to a certain degree, gradually shut out the water, and remain for ever in the form of dry land.

            But, to remove every doubt concerning this important point, let us examine more closely the practicability of a mountain’s being formed at the bottom of the sea, by the motion and se- [19] dements of the water. On a coast which the sea washes with violence during the flow, some part of the earth must be carried off by every stroke of the waves.  Even where the sea is bounded by rock, it is a known fact, that the rock is gradually wasted by the water,* and, consequently, that small particles are carried off by the retreat of every wave.  Those particles of earth or stone are necessarily transported to some distance.  Whenever the agitation of the water is abated, the particles are precipitated in the form of sediment, and lay the foundation of a first stratum, which is either horizontal, or inclined, according to the situation of the surface upon which they fall.  This stratum will soon be succeeded by a similar one, produced by the same cause; and thus a considerable quantity of matter will be gradually amassed, and disposed in parallel beds.  In process of time, this gradually accumulating mass will become a mountain in the bottom of the sea, exactly resembling, both in external and internal structure, these mountains which we see on the dry land.  If there happened to be shells in that part of the bottom of the sea where we have supposed the sediments to be deposited, they will be covered, filled, and incorporated with the deposited matter, and form a part of the general mass.  These shells will be lodged in different parts of the mountains, correspon- [20] ding to the times they were deposited.  Those which lay at the bottom, before the first stratum was formed, will occupy the lowest station; and those which were afterwards deposited, wil be found in the more elevated parts.

            In the same manner, when the bottom of the sea, at particular placed, is troubled by the agitation of the water, earth, clay, shells, and other matter, must necessarily be removed from these parts, and deposited elsewhere.  For we are assured by all divers, that the bottom of the sea, at the greatest depths to which they descend,* is so strongly affected by the agitation of the water, that earth, clay, and shells, are removed to great distances.  Transportations of this kind must, therefore, be constantly going on in every part of the ocean; and the matters transported, after subsiding, must uniformly raise eminences similar, in every respect, to the composition and structure of our mountains.  Thus the motions produced by the flux and reflux, by winds and currents, must uniformly create inequalities in the bottom of the ocean.

            Further, we must not imagine that these matters cannot be carried to great distances, since we daily find grain, and other productions of the East and West Indies, arriving on our casts.⁺  These bodies are, indeed, specifically lighter than water; but the other substances [21] are specifically heavier.  Still, however, as they are reduced to an impalpable powder, they may be kept long suspended in the water, and, of course, transported to any distance. 

            It has been conceived, that the agitation produced by the winds and tides is only superficial, and does not affect the bottom, especially when it is very deep.  But it ought to be remembered, that, whatever be the depth, the whole mass is put in motion by the tides at the same time; and that, in a fluid globe, this motion would be communicated even to the centre.  The power which occasions the flux and reflux is penetrating; it acts equally upon every particle of the mass; so that the quantity of its force, at different depths, may be determined by calculation.  Indeed, this point is so certain, that it admits not of dispute. 

            We cannot, therefore, hesitate in pronouncing, that the tides, the winds, and every other cause of motion in the sea, must produce heights and inequalities in its bottom; and that these eminences must uniformly be composed of regular strata, either horizontal or inclined. These heights will gradually augment; like the waves which formed them, they will mutually respect each other; and, if the extent of the base be great, in a track of years, they will form a vast chain of mountains.  Whenever eminences are formed, they interrupt the uniform motion of the waters, and produce new motions, known [22] by the name of currents.  Between two neighbouring heights in the bottom of the ocean, there must be a current,* which will follow their common direction, and, like a river, cut a channel, the angles of which will be alternately opposite through the whole extent of its course.  These heights must continually increase; for, during the flow, the water will deposite [sic] its ordinary sediment upon their ridges, and the waters which are impelled by the current will force along, from great distances, quantities of matter, which will subside between the hills, and, at the same time, scoup [sic] out a valley with corresponding angles at their foundation.  Now, by means of these different motions and sediments, the bottom of the ocean, though formerly smooth, must soon be furrowed, and interspersed with hills and chains of mountains, as we actually find it at present.  The soft materials of which the eminences were originally composed, would gradually harden by their own gravity.  Such of them as consisted of sandy and crystalline particles, would produced those enormous masses of rock and flint in which we find crystals and other precious stones.  Others, composed of stony particles mixed with shells, give rise to those beds of lime-stone and marble, in which vast quantities of sea-shells are still found incorporated.  Lastly, all our beds of marle [sic]  and chalk have derived their origin from particles of shells mix- [23] ed with pure earth, collected and deposited at particular places in the bottom of the sea.  All these substances are disposed in regular strata; they all contain heterogenous matter, and vast quantities of sea-bodies situated nearly in proportion to their specific gravities.  The lighter shells are found in chalk; the heavier in clay and lime-stone.  These shells are uniformly filled with the matter in which they are found, whether it be stone or earth; an incontestable proof, that they have been transported along with the matter which fills and surrounds them, and that this matter was then in the form of an impalpable powder.  In a word, all those substances, the horizontal situation of which has arisen from the waters of the sea, invariably preserve their original position.

            It may be here objected, that most hills whose summits consist of solid rocks of moor-stone, or of marble, are founded upon small eminences, composed of less heavy materials, of clay, for example, or of light sand, the strata of which commonly extend over the neighbouring plains.  If the above theory be just, what could bring about an arrangement so singular, so contrary to the laws of gravity?  But this phaenomenon admits of an easy and natural explication.  The waters would operate first upon the upper stratum, either of coasts, or the bottom of the sea:  This upper stratum consists generally of clay or sand; and these light substances, being carried [24] off and deposited previous to the more dense and solid, they would of course form small eminences, and become foundations for the more heavy particles to rest upon.  After the light superficial substances are removed, the harder and more ponderous would next be subjected to the attrition of the water, reduced to a fine powder, and carried off and deposited above the hillocks of sand or clay.  These small stony particles would, in a succession of ages, form those solid rocks which we now find on the tops of hills and mountains. As particles of stone are heavier than sand or clay, it is probable that they were originally covered and pressed by superior strata of considerable depth; but that they now occupy the highest stations, because they were last transported by the waves.

            To confirm this reasoning, let us investigate more minutely the situation of those materials which compose the superficial part of the globe, the only part of which we have any adequate knowledge.  The different strata of stones in quarries are almost all horizontal or regularly inclined.  Those founded upon hard clay, or other solid matter, are evidently horizontal, especially in plains.  The disposition of quarries, where flint or brownish free-stone are found in detached portions, is indeed less regular.  But ever here the uniformity of nature is not interrupted; for the horizontal or regularly inclining position of the strata is apparent in granite and [25] brown free-stone, wherever they exist in large connected masses.  This position is universal, excepting in flint and brown free-stone in small detached portions, substances, the formation of which we shall demonstrate to have been posterior to those just now mentioned.  The strata of granite, vitrisiable [sic] sand, clays, marbles, calcareous stones, chalk, and marles, are always parallel or equally inclined.  In these the original formation is easily discoverable; for the strata are exactly horizontal, and very thin, being placed above each other like the leaves of a book.  Beds of sand, of soft and hard clay, of chalk, and of shells, are likewise either horizontal or uniformly inclined.  Strata of every kind preserve the same thickness through their whole extent, which is often many leagues, and might, by proper observations, be traced still farther.  In a word, the disposition of strata, as deep as mankind have hitherto penetrated, is the same.

            Those beds of sand and gravel which are washed down from mountains must, in some measure, be excepted from the general rule.  They are sometimes of a considerable extent in valleys, and are situated immediately under the soil, or first stratum.  In plains, they are level, like the more antient and interior strata.  But near the bottom, or upon the ridges of hills, they have an inclination corresponding to that of the ground upon which they have been deposited.  As these beds of sand and gravel are [26] formed by rivers and brooks, which, especially in the valleys, often change their channels, it is not surprising that they should be so frequent.  A small rivulet is sufficient, in a course of time, to spread a bed of sand or gravel over a very large valley.  In a champaign [sic] country, surrounded with hills, whose base, as well as the upper stratum of the plain, consisted of a hard clay, I have often observed, that, above the origin of the brooks or fivers, the clay was situated immediately under the vegetable stratum; but, in the low grounds, there was a stratum of sand, about a foot thick above the clay, extending to a great distance from the banks of the rivers.  The strata formed by rivers are not very antient; they are easily distinguished by their frequent interruptions, and the inequality in thickness, which is constantly varying; but the antient strata uniformly preserve the same dimensions through their whole extent.  Besides, these modern strata may be distinguished, with certainty, by the form of the stones and gravel they contain, which bear evident marks of having been rolled, smoothed, and rounded by the motion of water. The same observation may be made with regard to those beds of turf, and corrupted vegetables, which are found in marshy grounds, immediately below the soil:  They have no claim to antiquity, but have derived their existence from successive accumulations of decayed trees, and other plants.  The strata of slime, or mud, [27] which occur in many places, are also recent productions, having been formed by stagnating waters, or the inundations of rivers.  They are not so exactly horizontal, or so uniformly inclined, as the more antient strata, produced by the regular motions of the sea.  In strata formed by rivers, we meet with river, but seldom with sea shells; and the few that occur are broken, detached, and placed without order.  But, in the antient strata, there are no river-shells; the sea-shells are numerous, well preserved, and all placed in the same manner, having been transported and deposited at the same time, and by the same cause.  From whence could this beautiful regularity proceed?  Instead of regular strata, why do we not find the matters composing the earth huddled together without order?  Why are not rocks, marbles, clays, marles, &c. scattered promiscuously, or joined by irregular or vertical strata?  Why are not heavy bodies uniformly found in a lower situation than light ones?  It is easy to perceive, that this uniformity of nature, this species of organization, this union of different materials by parallel strata, without regard to their weights, could only proceed from a cause equally powerful and uniform as the motions of the sea, produced by regular winds, or by the flux and reflux, &c.

            These causes act with superior force under the equator than in other climates; for there the tides are higher, the winds more uni- [28] form.  The most extensive chains of mountains are likewise in the neighbourhood of the equator.  The mountains of Africa and Peru are the highest in the world, often extending through whole continents, and stretching to great distances under the waters of the ocean.  The mountains of Europe and Asia, which extend from Spain to China, are not so elevated as those of Africa and South America.  According to the relations of voyagers, the mountains of the north are but small hills, when compared to the mountains of the equatorial regions.  Besides, in the northern seas, there are few islands; but, in the Torrid Zone, they are innumerable.  Now, as islands are only the summits of mountains, it is apparent, that there are more inequalities on the surface of the earth, near the equator, than in northerly climates.

            Those prodigious chains of mountains which run from west to east in the Old Continent, and from north to south in the New, must have been formed by the general motion of the tides.  But the origin of the less considerable mountains and hills, must be ascribed to particular motions, occasioned by winds, currents, and other irregular agitations of the sea:  Their formation may, indeed, be owing to a combination of all those motions, which are capable of infinite variations; for the winds, and the situation of different islands and coasts, constantly change the natural course of the tides, making them [29] run in every possible direction.  It is, therefore, by no means surprising to see considerable eminences having no determined direction in their courses.  But, for our present purpose, it is sufficient to have shown, that mountains have not been produced by earthquakes, or other accidental causes, but that they are effects equally resulting from the general laws of nature, as their peculiar structure, and the situation of the materials of which they are composed.

            But how has it happened, that this earth, which we and our ancestors have inhabited for ages, which, from time immemorial, has been an immense continent, dry, compact, and removed from the reach of the water, should, if formerly the bottom of an ocean, be now exalted to such a height above the waters, and so compleatly [sic] separated from them? Since the waters remained so long upon the earth, why have they now deserted it?  What accident, what cause, could introduce a change so great?  Is it even possible to conceive a cause possessed of power sufficient to operate such an amazing effect?

            These are difficult questions.  But, as the facts are uncontrovertible, the precise manner in which they have happened may remain a secret, without prejudice to the conclusions which ought to be drawn from them.  A little reflection, however, will furnish us at least with [30] plausible solutions.*  We daily observe the sea gaining ground on certain coasts, and losing it on others.  We know, that the ocean has a general and uniform motion from east to west; that it makes violent efforts against the rocks and low grounds which encircle it; that there are whole provinces which human industry can hardly defend from the fury of the waves; and that there are instances of islands which have but lately emerged from the waters, and of regular inundations.  History informs us of inundations and deluges of a more extensive nature.  Ought not all this to convince us, that the surface of the earth has experienced very great revolutions, and that the sea may have actually given up possession of the greatest part of the ground which it formerly occupied?  For example, let us suppose, that the Old and New worlds were formerly but one continent, and that, by a violent earthquake, the antient Atlantis of Plato was sunk.  What would be the consequence of such a mighty revolution?  The sea would necessarily rush in from all quarters, and form what is now called the Atlantic Ocean; and vast continents, perhaps those which we now inhabit, would, of course, be left dry.  This great revolution might be effected by the sudden failure of some immense cavern in the interior part of the globe, and an universal deluge would infallibly succeed.  I would rather incline to [31] think that such a revolution would not be suddenly accomplished, but that it required a very long period.  However these conjectures stand, it is certain, that the revolution has happened, and I even believe that it happened naturally; for, if a judgment of the future is to be formed from the past, we have only to attend carefully to what passes before our eyes.  It is a fact, established by the repeated observation of voyagers, that the ocean has a constant motion from east to west.  This motion, like the tradewinds, is not only perceived between the tropics, but through the whole temperate climates, and as near the poles as navigators have approached.  As a necessary consequence of this motion, the Pacific Ocean must make continual efforts against the coasts of Tartary, China, and India; the Indian Ocean must act against the east coast of Africa; and the Atlantic must act in a similar manner against all the eastern coasts of America.  Hence the sea must have gained, and will always continue to gain on the east, and to lose on the west.  This of itself would be sufficient to prove the possibility of the change of sea into land, and of land into sea.  If such is the natural effect of the sea’s motion from the east to west, may it not reasonably be supposed, that Asia, and all the eastern continent, is the most antient country in the world?  and that Europe, and part of Africa, especially the west parts of these continents, as Britain, France, Spain, &c. [32] are countries of a more recent date?  Both history and physics concur in establishing this hypothesis.

            But, besides the constant motion of the sea from east to west, other causes concur in producing the effect just mentioned.  There are many lands lower than the level of the sea, and defended only by a narrow isthmus of rock, or by banks of still weaker materials.  The action of the waters must gradually destroy these barriers, and, consequently, such lands must then become part of the ocean.  Besides, the mountains are daily diminishing, part of them being constantly carried down to the valleys by rains.  It is likewise well known, that every little brook carries earth, and other matters, from the high grounds into the rivers, by which they are at last transported to the ocean.  By these means, the bottom of the sea is gradually filling up, the surface of the earth is approaching to level, and nothing but time is wanting for the sea’s successively changing place with the land.

            I speak not here of causes removed beyond the sphere of our knowledge, of those convulsions of nature, the slightest throe of which would be fatal to the globe.  The near approach of a comet, the absence of the moon, or the introduction of a new planet into the system, &c. are suppositions upon which the imagination may rove at large.  Causes of this kind will produce any effect we chuse.  From a single hy- [33] pothesis of this nature, a thousand physical romances might be drawn, and their authors might dignify them with the title of Theory of the Earth.  As an historian, I reject these vain speculations:  They depend upon mere possibilities, which, if called into action, necessarily imply such a devastation in the universe, that our globe, like a fugitive particle of matter, escapes our observation, and is no longer worthy of our attention.  But, to give consistency to our ideas, we must take the earth as it is, examine its different parts with minuteness, and, by induction, judge of the future, from what at present exists.  We ought not to be affected by causes which seldom act, and whose action is always sudden and violent.  These have no place in the ordinary course of nature.  But operations uniformly repeated, motions which succeed one another without interruption, are the causes which alone ought to be the foundation of our reasoning. 

            Some examples shall be given: We shall combine particular effects with general causes, and give detail of facts, which will illustrate and explain the different alterations that the earth has undergone, whether by irruptions of the sea upon the land, or by the sea’s retiring from lands which it formerly covered.

            That irruption which gave rise to the Mediterranean,* is undoubtedly the greatest.⁺  The [34] ocean runs with prodigious rapidity through a narrow passage between two promontories,* and then forms a vast sea, which, exclusive of the Black Sea, is about seven times larger than the kingdom of France. The motion through the Straits of Gibraltar is contrary to the motion in every other strait.  The general motion of the sea is from east to west; but, in the Straits of Gibraltar, it is from west to east:  An incontestable proof, that the Mediterranean Sea is not an antient gulf, but that it has been formed by an irruption, produced by some accidental cause, such as an earthquake swallowing up the barrier, or a violent effort of the ocean, occasioned by the wind’s forcing its way through the bank, between the two promontories of Gibraltar and Ceuta.  This opinion is supported by the testimony of the antients,+ who inform us, that there was a time when the Mediterranean had no existence.  It is likewise confirmed by natural history, and by observations upon the strata in the opposite coasts of Africa and Spain, where, as in neighbouring mountains, the beds of earth and stone are precisely the same at the same levels.

            When the ocean forced this passage, it ran through the Straits with much more rapidity than at present, and instantly deluged that large tract of land which formerly joined Europe to [35] Africa.  The waters covered all the grounds which were lower than the level of the ocean; and no part of them is now to be seen, except the tops of some of the mountains, such as part of Italy, Sicily, Malta, Corsica, Sardinia, Cyprus, Rhodes, and the islands of the Archipelago.

            I have not mentioned the Black Sea as an effect of this irruption; because the quantity of water it receives from the Danube, the Nieper, the Don, and other rivers, is more than sufficient both to form and support it.  Besides, it runs with great rapidity through the Bosphorus [sic] into the Mediterranean.*  It may even be supposed, that the Black and Caspian Seas were only two large lakes, which were perhaps joined by a narrow communication, or rather by a morass, or small lake, uniting the Don and the Wolga [sic] about Tria, where these two rivers run very near each other. It is likewise probable, that these two seas, or lakes, were formerly of a much greater extent; for the large rivers which fall into the Black and Caspian Seas must have gradually brought down a quantity of earth and sand sufficient to stop up the communication, and to form that neck of land by which these two seas are divided.  We know, that large rivers, in a course of time, block up seas, and form new lands, as in the province at the mouth of the Yellow river in China; Louisiana at the [36] mouth of the Missisippi [sic]; and the northern part of AEgypt, which derived its existence* from the inundations of the Nile.⁺  Such quantities of earth are brought down, by the rapidity of the Nile, from the interior parts of Africa, and deposited during the inundations, that you may dig fifty feet deep before you can reach the bottom of the slime and mud.  Louisiana, and the province of the Yellow river have, in the same manner, been original formed by the slime of rivers.

            Farther, the Caspian Sea is a real lake.  It has no communication with any other sea, not even with the Lake Aral, which appears to have been a part of it, being only separated by a large tract of sand, in which neither river nor canal for carrying off the waters have been discovered.  This sea, therefore, has no external communication with any other; and I doubt much if there is any reason to suspect a subterraneous communication with the Black Sea, or with the Gulf of Persia.  The Caspian, it is true, receives the Wolga, and several other rivers, which appear to furnish as much water as is lost by evaporation.  But, independent of the difficulties attending such calculations, if it communicates with any other sea, a uniform and rapid current towards the place of communication would be an infallible consequence; but no such thing has yet been discovered.  Travellers of the best credit [37] assure us of the contrary; we, therefore, conclude, that the Caspian Sea receives just as much water from the rivers and clouds as it loses by evaporation. 

            It is not improbable, that the Black Sea will, some time or other, be entirely divided from the Mediterranean; and that the Bosphorus will be chocked up, whenever the rivers shall have accumulated a sufficient quantity of materials to bring about this effect.  It is impossible to fix the aera [sic] of this event; but time, and the diminution of waters in rivers, in proportion as the mountains are lowered by the causes mentioned above, will one day exhibit this phaenomenon to the world. 

            The Caspian and Black Seas should, therefore, be considered rather as lakes than as gulfs of the ocean; because they exactly resemble other lakes that receive a number of rivers without any visible outlet, as the Dead Sea, several lakes in Africa, and elsewhere. Besides, the saltness [sic] of these two seas is not nearly equal to that of the Mediterranean or the ocean; and it is an agreed point, that the navigation in the Caspian and Black seas, on account of their numberless shoals, rocks, and banks, is so extremely hazardous, that only small vessels can be used in them with safety.  This circumstance proves farther, that these seas ought not to be considered as gulfs of the ocean, but as vast collections of water amassed by large rivers.  [38]

            If the isthmus which separates Africa from Asia were cut, it would necessarily create a great irruption of the sea upon the land.  This was formerly projected by the Kings of Aegypt, and adopted since by the Califs.  I doubt whether the pretended communication between the Red Sea and Mediterranean be sufficiently established.  The Red Sea is a narrow branch of the ocean:  Through its whole extent, not a single river runs into it from the Aegyptian side, and very few from the opposite.  This sea will not, therefore, be subject to diminution, like those seas or lakes which are actually impaired by the slime and sand brought down by large rivers.  The Red Sea receives all its waters directly from the ocean, and the motion of the tides in it are very discernible; of couse, it must be affected by the general motions of the ocean.  The Mediterranean, on the other hand, must be lower than the ocean; because the current through the Straits is exceedingly rapid.  Besides, it receives the Nile, which runs parallel to the west coast of the Red Sea, and passes through the longest extent of AEgypt, which is a very low country. From these circumstances, it is at least probable, that the Red Sea is higher than the Mediterranean, and, consequently, that, if the isthmus of Suez were cut, a great inundation, and a considerable augmentation of the Mediterranean, would ensue; especially if the waters were not restrained by dikes and sluices placed at proper distances.  [39]  This precaution was probably used, if ever the antient canal existed.

            But, not to spend too much time on conjectures, which, however well founded, may perhaps appear rash, we shall give some certain and recent examples of the changes of sea into land, and of land into sea.*  At Venice, the bottom of the sea is constantly rising:  If the canals had not been carefully kept clean, the moats and city would, long ere now, have formed a part of the continent.  The same thing may be said of most harbours, bays, and mouths of rivers.  In Holland, the bottom of the sea is elevated in many places; the gulf of Zuderzee and the straits of the Texel, cannot receive such large vessels as formerly.  At the mouth of almost every river, we find small islands, and banks of earth and sand brought down from the higher grounds; and it is uncontravertible [sic], that the sea is constantly dammed up, wherever great rivers empty themselves.  The Rhine is lost in the sands which itself ha accumulated.  The Danube, the Nile, and all large rivers, after having transported great quantities of slime, sand, &c. never more arrive at the sea by a single channel; they split into branches, the intervals of which consist of the materials which they themselves have transported.  Marshes are daily drained; lands, abandoned by the sea, are now plowed and sown; we navigate whole countries now covered by the [40] waters; in a word, we see so many instances of land changed into water, and water into land, that we must be convinced of the continual, though slow progress of such changes in all places.  So that, in time, the gulfs of the ocean will become continents; the isthmuses will be changed into straits; and the tops of the mountains will be metamorphosed into shoaly [sic] rocks in the sea.

            The waters, then, have covered, and may still cover, every part of the earth which is now dry.  Our astonishment at finding the productions of the sea dispersed every where, and a composition of bodies which could not be effected by any other means than the operation of the waters, ought forever to cease.  We have already explained how the horizontal strata of the earth were formed.  But those perpendicular fissures, which are equally diffused through rocks, clays, and every constituent material of the globe, remain to be considered.  The perpendicular fissures are indeed placed at greater distances from each other than the horizontal; and the softer the matter, the more distant are the fissures.  In marble and hard stone, the fissures are only a few feet asunder.  If the mass of rock be extensive, the distance betwixt the fissures is some fathoms:  Sometimes they extend from the summit to the base of the rock, and sometimes they terminate after arriving at a horizontal fissure.  They are uniformly perpendicular in the strata [41] of all calcareous substances, as chalk, marles, marble, &c.  But they are more oblique and less regularly situated, in vitrescent [sic] bodies, brown free-stone, and rocks of flint, where they are often adorned with crystals and other minerals.  In quarries of marble, or of calcareous stone, the fissures at [sic] filled with spar, gypsum, gravel, and an earthy sand, which contains a considerable portion of chalk.  In marles, and every other species of earth, except sand-stone, the perpendicular fissures are either empty or filled with such matters as have been transported thither by water.

            The cause of perpendicular fissures is easily investigated.  As various materials constituting the different strata were transported by the waters, and deposited in the form of sediments, they would at first be in a very diluted state, and, would gradually harden and part with the superfluous quantity of water they contained.  In the process of drying, they would naturally contract, and of course split at irregular distances.  These fissures necessarily assumed a perpendicular direction; because, in this direction, the action of gravity of one particle upon another is equal to nothing; but it acts directly opposite to this description in a horizontal situation:  The diminution in bulk could have no sensible effect but in a vertical line.  I say, the contraction of the parts in drying, not the contained water forcing an issue, as has been alledged, is the cause [42] of perpendicular fissures; for I have often remarked, that the sides of those fissures, through their whole extent, correspond as exactly as the two sides of a split piece of wood.  Their surfaces are rude and irregular; whereas, if they had taken their rise from the motion of water, they would have been smooth and polished.  Hence these fissures must have been produced, either suddenly or gradually, by drying and contracting, like the cracks and fissures in green wood; and the greatest part of the water the bodies contained, must have evaporated by the pores.  In the chapter upon minerals, we shall demonstrate, that some part of the original water still remains in stones and several other substances; and that crystals, minerals, and some other bodies, owe their existence to this water.

            Perpendicular fissures vary greatly as to the extent of their openings.  Some are about half an inch, or an inch, others a foot, or two feet; some extend several fathoms, and give rise to those vast precipices which so frequently occur between opposite parts of the same rocks in the Alps and other high mountains.  It is plain, that the fissures, the openings of which are small, have been occasioned solely by drying.  But those which extend several feet, are partly owing to another cause; namely, the sinking of the foundation upon one side, while that of the other remains firm.  If the base sinks but a line or two, when the height of the rock is conside- [43] rable, an opening of several feet, or even fathoms, will be the consequence.  When rocks are founded on clay or sand, they sometimes slip a little to a side; and the fissures are of course augmented by this motion.  I have not hitherto mentioned those large openings, those prodigious cuts which are to be met with in rocks and mountains:  These could not be produced by any other means than the sinking of immense subterraneous caverns that were unable longer to sustain their incumbent load.  But these cuts or intervals in mountains are not of the same nature with perpendicular fissures:  They appear to have been ports opened by the hand of nature for the communication of nations.  This seems to be the intention of all large openings in chains of mountains, and of those straits by which different parts of the ocean are connected; as the Straits of Thermopyle, of Gibraltar, &c.; the gaps of ports in Mount Caucasus, the Cordeliers, &c.  A simple separation, by the drying of matter, could not produce this effect:  Large portions of earth must have been sunk, swallowed up, or thrown down.*

            These great sinkings, though occasioned by accidental and secondary causes,⁺ are leading facts in the history of the earth, and have contributed greatly in changing the appearance of its surface.  Most of them have been produced by subterraneous fires, the explosions of which [44] give rise to earthquakes and volcano’s.  The force of inflamed matter shut up in the bowels of the earth is irresistible.*  By the action of subterraneous fires, whole cites have been swallowed up, mountains, and large tracts of country have been overturned and rendered unfit for the habitation of men.  But, though this force be great, though its effects appear to be prodigious, we cannot assent to the opinions of some authors, who suppose that these subterraneous fires are only branches of the earth.  Neither do we credit the common notion, that these fires have their seat at a great depth below the surface; for matter cannot begin to burn, or at least the inflammation cannot be supported, without air.  In examining the materials that issue from volcano’s, even in their most violent eruptions, it is easy to perceive that the furnace is not very deep, and that the inflamed substances are the same with those on the top of the mountain, only disfigured by calcination and the melting of the metallic particles they contain.  To be convinced that the matter thrown out by volcano’s do not come from any considerable depth, we need only attend to the height of the mountain, and consider the immense force which would be necessary to project stones and minerals to the height of half a league; for Aetna, [45] Hecla, and other volcano’s, have at least that elevation.

            Now, it is well known, that fire acts equally on all sides; it cannot, therefore, act upwards with a force sufficient to throw large stones half a league high, without an equal re-action on the base and sides.  But the sides of the mountain would very soon be pierced and blown to pieces by this re-action; because the materials of which it consists are not more dense or firm that those which are projected.  How, then, can it be imagined, that the cavity, which must be considered as the tube or cannon, could possibly resist a force necessary to raise such heavy bodies to the mouth of the volcano?  Besides, suppose the cavity deeper, as the external orifice is not great, it would be impossible for so large a quantity of liquid and burning matters to issue forth at a time, without clashing against each other, and against the irregular sides of the cavity; and, in passing through so long a space, they would be in danger of cooling and congealing.  Rivers of melted sulphur and bitumen, projected from volcano’s along with stones and minerals, run from the tops of the mountains into the plains.  Is it natural to think, that matter so fluid, so little able to resist violent action, could be projected from a very great depth?  Every observation which can be made on this subject will tend to prove, that the fire in volcano’s is not very distant from the tops of the [46] mountains, and never descends so low as the level of the plains.*

            This account of volcano’s, however, is not inconsistent with their being the cause of considerable earthquakes; neither does it contradict the communication of one volcano with another, by means of subtertaneous [sic] passages.⁺  But the depth of the furnace is the object our present investigation; and it cannot be very distant from the mouth of the volcano.  To produce an earthquake in a plain, it is not necessary that the bottom of the volcano should be below the level of that plain, nor that there should be subterraneous cavities filled with the same burning matter under it.  A violent explosion, with which eruptions are uniformly accompanied, may, like that of a power-magazine, give such a concussion as to produce, by its reaction, an earthquake of considerable extent.

            I mean not to say that there are no earthquakes which derive their existence from subterranean fires;³ but that there are earthquakes produced solely by the explosion of volcano’s.  In confirmation of what has been said upon this subject, volcano’s seldom or never appear in plains; on the contrary, their mouths, or craters, are always found on the tops of the highest mountains.  If the subterraneous fire of volcano’s stretched below the plains, would not [47] new passages be opened there during violent eruption, rather than in the tops of the mountains, where the resistance is greater?  In the first eruption, would it not have been easier to pierce a plain, than a mountain of half a league in height?

            It is not difficult to discover the reason why volcano’s appear only in mountains.  Greater quantities of minerals, sulphur, and pyrites, exist in mountains, and nearer the surface than in plains.  The mountains have likewise this farther advantage; they are more subject to the impressions of the air, and receive more rain and moisture, by which mineral substances are capable of being fermented to such a degree as to produce actual inflammation.

            To conclude, it has often been observed, that, after violent eruptions, the mountains have sunk and diminished, nearly in proportion to the quantity of matter thrown out, which is another proof that volcano’s are not so deep as the base of the mountains, and even that they are not much below the summit.

            In many places, earthquakes have formed considerable hollows, and even some large gaps in mountains.  All other inequalities are coeval with the mountains themselves, and owe their existence to currents in the ocean; for, in every place which has not been disturbed by accidental convulsions, the strata of mountains are pa- [48] rallel, and their angles correspond.*  It is not difficult to distinguish subterraneous caverns and excavations formed by volcano’s, from those produced by water.  The latter consist only of solid rocks, the sand and clay with which they were formerly filled being carried off by water, which is the origin of caverns in hills; for those found in plains are commonly nothing but old pits and quarries, like the salt-quarries of Maestricht, the mines of Poland, &c.  But natural caverns are proper to the mountains; the summit, or higher parts, furnish them with water, which afterwards issues out to the surface where-ever it can find a passage.  These are the sources of springs and rivers.  When a large cavern of this kind is suddenly filled up by the falling of its roof, an inundation is generally the consequence.⁺

            From these facts, it is easy to perceive how much subterraneous fires have contributed to change both the surface and internal part of the globe.  This cause has power enough to produce very great effects. But it is difficult to conceive how any sensible alterations upon the land can be introduced by the winds.³  Their dominion would appear to be confined to the sea.  Indeed, next to the tides, nothing has such a powerful influence upon the waters; the flux and reflux proceed with an uniform pace; their [49] operations are always the same; but the action of the winds is capricious and violent.  They rush on with irresistible fury, and excite such impetuous commotions, that the ocean, from a smooth and tranquil plain, in an instant is furrowed with waves that emulate the height of mountains, and dash themselves in pieces against the shores.  The surface of the ocean is subject to constant alterations from the winds.  But ought not the surface of the land, which has so solid an appearance, ever to remain uninfluenced by a cause of this kind?  It is consonant to experience, however, that the winds raise mountains of sand in Arabia and Africa; that they overwhelm large plains with it; and that they frequently carry these sands many leagues into the sea, where they accumulate in such quantities as to form banks, downs, and even islands.*  It is also well known, that hurricanes are the scourge of the Antilles, of Madagascar, and of other countries, where their impetuosity is so great, that they sweep away trees, plants, and animals, together with the soil which nourished them.  They drive back, they annihilate rivers, and produce new ones; they overthrow rocks and mountains; they scoup [sic] out holes and gulphs in the earth, and totally change the face of those unhappy countries that give birth to them.  Hap- [50] pily, few climates are exposed to the violence of those dreadful agitations of the air.

            But the greatest changes upon the surface of the earth are occasioned by rains, rivers, and torrents from the mountains.  These derive their origin from the vapours raised by the sun from the surface of the ocean, and which are transported by the winds through every climate.  The progress of these vapours, which are supported by the air, and transported at the pleasure of the winds, is interrupted by the tops of the mountains, where they accumulate into clouds, and fall down in the form of rain, dew, or snow.  At first, these waters descended into the plains without any fixed course;* but they gradually hollowed out proper channels for themselves.  By the power of gravity, they ran to the bottom of the mountains, and, penetrating or dissolving the lower grounds, they carried along with them sand and gravel, cut deep furrows in the plains, and thus opened passages to the sea, which always receives as much water by rivers, as it loses by evaporation.  The windings in the channels of rivers have uniformly corresponding angles on their opposite banks; and, as mountains and hills, which may be regarded as the banks of the valleys by which they are separated, have likewise sinuosities [sic] with corresponding angles, this circumstance seems to demonstrate, that the valleys have been gradually formed by [51] currents of the ocean, in the same manner as the channels of rivers have been produced.

            The waters with run upon the surface, and support the verdure and fertility of the soil, compose not perhaps one half of the quantity that is produced by vapour.  Numberless veins of water sink deep into the bowels of the earth.  In some places, you are certain of obtaining water by digging; in others, none can be found.  In almost all the valleys and low grounds, at a certain depth, water is uniformly to be met with.  But, in all high grounds, it is impossible to extract water from the bowels of the earth.  It must be collected from the heavens.  There are extensive countries where no wells can be obtained; there men, and other animals, are supplied with drink from cisterns and pools.  In the east, and especially in Arabia, AEgypt, and Persia, wells and springs are great and valuable rarities. To supply their place, the inhabitants have been obliged to make large reservoirs to collect the water that falls from the heavens.  These works, projected and executed from public necessity, constitute the most beautiful and magnificent monuments of the east.  Some eastern reservoirs have more than two square leagues of superficies, and fertilize whole provinces by numberless ducts and canals let out from all sides.  But, in plain countries, furnished with large rivers, it is impossible to break the surface of the earth without finding water.  In camps situated in [52] the neighbourhood of rivers, it often happens, that every tent may have its own well, by giving a few strokes with a pick-ax.

            Most of the water, so liberally diffused through low grounds, comes from the neighbouring hills and eminences. During great rains, or the sudden melting of snow, part of the water runs upon the surface; but most of it penetrates the earth and rocks, by means of small chinks and fissures.  This water rises again to the surface, whenever it can find an issue; but it often drills through sands, and creeps along till it finds a bottom of clay, or hard earth, and there forms subterraneous lakes, brooks, and perhaps rivers, of which the channels are for ever buried in oblivion.  Subterraneous rivers, however, must follow the general law of nature, and uniformly fun from the higher to the lower ground; their waters must of course either all at last into the sea, or be collected in some low place, whether at the surface, or in the bowels of the earth:  For there are several lakes which neither receive nor give rise to any river.  A still greater number receive no considerable river, but are the sources of the largest rivers on earth; as the lakes from which the river St Laurence issues; the lake Chiame, from which two large rivers arise, that water the kingdoms of Asem and Pegu; the lakes of Assinboil in America; those of Azera in Muscovy; those that give rise to [53] the Bog and the Irtis, and many others.*  It is plain, that these lakes must derive their existence from the waters of superior grounds, running through subterraneous passages.  Some, indeed, have affirmed, that lakes are to be met with on the tops of the highest mountains.  But this is incredible; for the lakes found on the Alps, and other elevated situations, are all overtopped by higher mountains, and derive their origin from the waters which run down the sides, or are filtered through the bowels of these superior eminences, in the same manner as the lakes in valleys are supplied.

            From this reasoning, the existence of subterraneous collections of water, especially under large plains, is apparent:⁺  For mountains, hills, and heights of every kind, are exposed on all sides to the weather.  The waters that fall upon their summits, and upon elevated plains, after penetrating the earth, must, from the declivity of the ground, break out at many places in the form of springs and fountains:  Of course, little water will be found in the bowels of mountains. But, in plains, as the water filtrated through the earth can find no issue, it must be collected in subterraneous caverns, or dispersed in small veins, among sand and gravel.  This is the origin of the water so universally diffused through low grounds.  The bottom of a pit or well, is only a small artificial bason [sic], into which the water in- [54] sinuates itself from the higher grounds.  At first it generally falls in by drops; but afterwards, when the passages become more open, it receives fresh supplies from greater distances, and runs in small continued veins or rills.  To this circumstance it is owing, that, although water may be found in anhy part of a plain, only a certain number of wells can be supplied.  This number is in proportion to the quantity of water diffused, or rather to the extent of the higher grounds from which it comes. 

            To find water, it is unnecessary to dig below the level of the river.  It is commonly found at smaller depths.  The water of rivers seldom spreads far in the earth by filtration.  Even what is found in the earth below the level of rivers, is not derived from them; for, in rivers which have been dried up, or whose courses have been changed, no greater quantity of water is obtained by digging, than in the neighbouring ground at an equal depth.  Five or six feet of earth is sufficient to contain water, and to prevent its escape:  I have often remarked, that the banks of rivulets or pools have no sensible moisture at the distance of six inches from the water.  It is true, the filtration is always in proportion to the penetrability of the ground.  But, upon examining the stagnating pools with a sandy bottom, it is remarkable that the moisture spreads but a few inches.  Neither is the extent of it great in a vegetable soil, which is [55] much more loose and porous than sand or hard earth.  A garden-bed, though plentifully watered, communicates little or no moisture to those adjoining.  I have examined level heaps of garden-earth, of six or eight feet thick, which had remained undisturbed for some years, and found that the rain-water had never reached above three or four feet deep.  I have made the same observation upon earth which had lain 200 years in ridges: Below the depth of three or four feet, it was as dry as dust.  Hence the spreading of water by filtration alone, is not so extensive as has generally been imagined.  Very little can descend in this way to the bowels of the earth.  But water, by its own gravity, descends from the surface to the greatest depths.  It sinks though natural conduits, or forces passages for itself:  It follows the roots of trees, the fissures of rocks, or their interstices.  It divides and expands on all hands into an infinite number of small branches or rills; and uniformly descends till its progress is stopped by clay or a solid earth, where it accumulates and breaks out to the surface in form of a spring or fountain.

            It would be no easy task to make an exact calculation of the quantity of subterraneous waters which have no apparent issue.*  Many pretend that it greatly surpasses all the waters on the surface:  Not to mention those who think that the interior part of the globe is entirely fill- [56] ed with water, it is imagined by some, that there is an infinite number of rivers, rills, and lakes in the bowels of the earth.  But this opinion seems to have no proper foundation; and it is probable, that the quantity of subterraneous waters which never appear at the surface, is very considerable; for, if the number of subterraneous rivers were so great, Why do we never see any of their mouths break out, like springs, on the surface?  Besides, rivers produce considerable changes on the surface of the earth; they carry off the soil; they wear away the most solid rocks, and remove every thing that opposes their passage.  The same effects would result from subterraneous rivers. But no such changes have ever been discovered; nothing below the surface is displaced; the different strata every where preserve their parallel and primitive position; and it is only in very few places that subterraneous veins of water, of any consideration, have been discovered.  Thus, the internal operation of water, though great, is not affected by the motion of it in large bodies:  As it is divided into an infinity of small veins, which are often shut up by numberless obstacles, it gives rise to many substances, which are totally different, both in form and structure, from those of the primitive matter.

            From what has been advanced, we may conclude, that the flux and reflux of the ocean have produced all the mountains, valleys, and other [57] inequalities of the surface of the earth; that currents of the sea have scouped out the valleys, elevated the hills, and bestowed on them their corresponding directions; that the same waters of the ocean, by transporting and depositing earth, &c. have given rise to the parallel strata; that the waters from the heavens gradually destroy the effects of the sea, by continually diminishing the height of the mountains, filling up the valleys, and choaking [sic] the mouths of rivers; and, by reducing every thing to its former level, they will, in time, restore the earth to the sea, which, by its natural operations, will again create new continents, interspersed with mountains and valleys, and every way similar to those which we now inhabit.

Notes

*  See subsequent proofs of the theory of the earth, art. I [back to page 1].

*  Whiston.  See the proofs, art. II [back to page 2].

*  Burnet.  See proofs, art. III [back to page 3].

+  Woodward.  See proofs, art. IV [back to page 3].

*  See Senec. Quaest. Lib. 6. cap. 21.  Strab. Geog. Lib. I.  Orosius, lib. 2. cap. 18.  Plin. Lib. 2. cap. 19.  Hist. de l’acad. des sciences, annee 1708, p. 23 [back to page 5].

+  See the proofs, art. XIV [back to page 5].

*  See proofs, art. VI  [back to page 6].

+  Phil. Trans. Abridged, vol. ii. P. 323 [back to page 6].

3.  Boyle’s works, vol. iii. p. 232 [back to page 6].

*  See proofs, art. I [back to page 7].

+  Proofs, art. XII [back to page 7].

3.  Proofs, art. XIII [back to page 7].

*  See M. Buache’s chart of the depths of the ocean between Africa and America [back to page 8].

+  Varenii Geog. Gen. p. 218 [back to page 8].

3.  Proofs, art. XIII [back to page 8].

4.  Varnen. P. 140. and Voyages de Pirard, p. 137 [back to page 8].

5.  Shaw’s travels [back to page 8].

6.  Proofs, art. XVI [back to page 8].

7.  The Maelstroom [sic]  in the Norwegian sea [back to page 8].

*  The calms and tornados in the Aethiopian sea [back to page 9].

+  Proofs, art. VI. And X [back to page 9].

3.  See Buache’s chart 1739 [back to page 9].

*  Profs, art. IX [back to page 10].

+  Ibid. art. IX. XII [back to page 10].

3.  Saliant and re entering angles; Muller’s fortification [back to page 10].

4.  Lettres Phil. De Bourguet, p. 181 [back to page 10].

5.  Varen, Geog. p. 69 [back to page 10].

*  Proofs, art. X [back to page 11].

+  Ibid. art. VII [back to page 11].

3.  Ibid. art. XVI [back to page 11].

4.  Kircher Mund. Subter. in praes. [back to page 11].

5.  Varen. Geog. p. 43 [back to page 11].

*  Proofs, art. VII [back to page 12].

+  Ibid. and Woodward, p. 41 &c. [back to page 12].

3.  Proofs, art. VIII [back to page 12].

4.  Proofs, art. VIII [back to page 12].

*  Steno, Woodward, Ray, Bourguet, Scheuchzer, Phil. Trans. Mem. De l’Acad. &c [back to page 13].

*  Proofs, art. VII [back to page 15].

*  Proofs, art. XVII [back to page 17].

*  Proofs, art. XII [back to page 18].

*  Proofs, art. XIX [back to page 19].

*  See Shaw’s travels  [back to page 20].

*  Boyle’s works, vol. 3. p. 232 [back to page 21].

+  Particularly on the coasts of Scotland and of Ireland; See Ray’s Discourses [back to page 21].

*  Proofs, art. XIII [back to page 23].

*  See proofs, art. XIX [back to page 31].

*  Proofs, art. XI. And XIX [back to page 34].

+  Ray’s Discourses, p. 209.; Plot. Hist. Nat. &c [back to page 34].

*  Phil. Trans. Abridged, vol. 2. p. 289 [back to page 35].

+  Diodorus Siculus, Strabo [back to page 35].

*  Phil. Trans. Abridged, vol. 2. p. 289 [back to page 36].

*  Shaw’s Travels [back to page 37].

+  Proofs, art. XIX [back to page 37].

*  Proofs, art. XIX [back to page 40].

*  Proofs, art. XVII [back to page 44].

+  Ibid.  [back to page 44].

*  Agricola de rebus quae effluent e terra.  Phil. Trans. Abrid. Vol. ii. P. 391.  Ray’s discourses, p. 272 [back to page 45].

*  Borelli de incendis Aetnae [back to page 47].

+  Phil. Trans. Abridged, vol. 2. p. 392 [back to page 47].

3.  Proofs, art. XVI [back to page 47].

*  Bellarmin. De ascen. Mentis in Deum. Varen. Geog. p. 282.  Voyag. De Pyrand, tom. 1. p. 470 [back to page 50].

*  See proofs, art. X. and XVIII [back to page 51].

*  Proofs, art. XI [back to page 54].

+  Proofs, art. XVIII [back to page 54].

*  Proofs, art. X. XI. And XVIII [back to page 56].