On this occafion, we scarce need to remind our Readers of Mr. Michel's happy application of this principle, in his paper on the caufe of earthquakes, published in the Philofophical Tranf

actions.

Fire, at first acting alone, and with an intenfity gradually increafing on the fuperincumbent ftrata, is fuppofed by the Author to have gradually distended and elevated those parts most, on which the Antediluvian ocean refted; as the primitive islands, by their additional weight of folid and heavy matter, opposed a greater refiftance. The waters thus raised would naturally flow towards the now lefs elevated folid parts, or antediluvian islands; and would finally cover them, fo as to produce an univerfal deluge.

The expanfion caused by fire ftill increafing, till its force became fuperior to the gravity, and cohefion, or tenacity of the incumbent firata; the latter would at length burft, and through the fiffures a communication would be opened between the water and the ignited melted matter below. By the fteam thus fuddenly generated, explofions must enfue, which must destroy the uniformity of the globe, fhatter it into fragments, produce immenfe mountains, and extenfive and deep fubterraneous caverns; into which laft the waters would afterwards defcend, and leave the various continents, mountains, &c. in the fame ftate nearly in which we now view them; and containing the fame fhells and other marine exuvia which they brought up with them from the bottom of the fea.-But we shall here leave the Author to speak for himself.

The terraqueous globe being thus burft into millions of fragments, and from a caufe apparently feated nearer to its center than its furface, muft certainly be thrown into ftrange heaps of ruins : for the fragments of the frata thus blown up, could not poffibly fall together again into their primitive order and regularity: therefore an infinite number of fubterraneous caverns must have been formed, probably many miles, or many hundreds of miles, below the bottom of the antediluvian fea.

Now it is eafy to conceive, when a body of fuch an immenfe magnitude as the earth was thus reduced to an heap of ruins, that its incumbent water would immediately defcend into the caverns and interftices thereof; and by approaching fo much nearer towards the center, than in its antediluvian ftate, much of the terreftrial furface would be left naked and expofed, with all its horrid gulphs, craggy rocks, mountains, and other diforderly appearances.

• Thus the primitive state of the earth feems to have been totally metamorphofed by the first convulfion of nature, at the time of the. deluge; its frata broken, and thrown into every poffible degree of confufion and diforder. Thus, thofe mighty eminences the Alps, the Andes, the Pyrenean mountains, &c. were brought from beneath the great deep-the fea retired from thofe vaft tracts of land, the continents become fathomlefs; environed with craggy rocks, cliffs, and

impending

impending fhores; and its bottom spread over with mountains and vallies like the land.

It is further to be observed of the horrid effects of this convulfionthat as the primitive lands were more ponderous and lefs elevated than the bottom of the fea, the former would more inftantaneously fubfide into the ocean of melted matter, than the latter; therefore, in all probability, they became the bottom of the pofidiluvian sea: and the bottom of the antediluvian fea being more elevated, was converted into the poftdiluvian mountains, continents, &c. This conjecture is remarkably confirmed by the vast number of foilil fhells, and other marine exuviæ, found imbedded near the tops of mountains, and the interior parts of continents, far remote from the fea, in all parts of the world hitherto explored.'

In this manner, and by employing a caufe that appears adequate to the effect, and which is known, even at this time, partially to exift; the Author at once accounts for the fingular appearances which the prefent earth exhibits on and beneath its furface, for the general deluge, and for its ceffation; and this he does, without having recourfe to comets, a fudden alteration of the earth's center of gravity, and other violent and purely gratuitous affumptions. A difficulty however remains, which he next prepares to folve.

The remains and impreffions of marine animals have not only, as we have already obferved, been found in all parts of the globe; but it is likewife well known that the exuvia, &c. of fhell fifh which now inhabit only the feas between the tropics and near the line, have been frequently found here in England, and in various other parts very remote from their prefent native climates; and fometimes depofited with as much order as beds of living fhell fish are in the fea. Thus for inftance, the chambered Nautilus, and remains of the Hawkes bill, Loggerhead, and Green Sea Tortoise, of Alligator's teeth, and of various shell fish, that now inhabit the Chinese ocean, or the Eaft and Weft Indies, have been found at Sheppy ifland, Richmond in Surry, and different parts of England. Remains, likewise, or impreffions of Crocodiles have been found in Derbyshire, Germany, &c.

Though these remains were depofited in these places at the æra of the deluge, or in confequence of the elevation of the ftrata, in which they are found, from the bottom of the Antediluvian ocean; the Author conceives it to be repugnant to common fense to suppose that these bodies could have been tranflated from their native beds in a distant climate, and brought into their prefent fituation by the waters of the deluge. He cannot admit that regular beds of oyfters, &c. for inftance, natives of the American feas, could have been removed fome thousand miles from their original feats, and depofited here with as much order as is obferved in the beds of living shell fish. On the contrary,

he

he affirms that they are now found in the very fame spot of the globe where they formerly lived and affociated: though fome of the fpecies do not, or perhaps cannot, exift in the fame latitudes, at present. The Author's attempt to folve the difficulty is principally founded on the following obfervation.

Animals might live, he alleges, in the primitive globe, univerfally covered with water, which cannot exift in the fame parts of the prefent globe, in confequence of the very great change in the temperature of climates, occafioned by the production of immenfe continents and mountains. From a confideration of the different properties of land and water, with respect to the tranfmitting or conducting of heat, the Author infers that the different regions of the primitive globe enjoyed a more equable température than the prefent, in confequence of the former having been uniformly covered with water, or containing iflands of fmall extent and elevation, and being thereby more extenfively adapted both to animal and vegetable life. On fimilar grounds he accounts for the longevity of our antediluvian forefathers; and ftill keeping an eye on Mofes, terminates his principal inquiry by a chapter on the poftdiluvian rainbow.

In the Appendix to this work are contained several curious particulars relative to the different ftrata of the mines in Derbyfhire, their arrangement, correfpondence, diflocations, and the changes they have undergone at different periods of time. Thefe obfervations are illuftrated by feveral plates, representing fections of them, in which their direction, fituation, depth, and other circumftances are fatisfactorily delineated. From this part of the work we cannot refift the temptation of extracting a few striking particulars.

One of the most remarkable of these ftrata is that called toadftone, black-ftone, channel, or cat-dirt, as it is variously denominated in different parts of these mining diftricts. This ftratum the Author pronounces to be as much a lava as that which flows from Hecla, Vefuvius, or Etna.' It is blackifh, very hard, and of a clofe texture; contains bladder-holes like the fcoria of metals, and has the fame chemical property of refifting acids. It feems to be the product of a later period than that of the limestone ftrata which it repeatedly feparates; and between which it evidently appears to have flowed, as well as to have filled up the fiffures that lay under it. Thefe limeftone ftrata contain various metallic ores, as well as figured ftones exhibiting the impreffions of numerous fpecies of marine animals; fome of which are not known to exift in the British seas *

The impreffion of a Crocodile likewife was found in a stratum of this ftone, in one of the Derbyshire mines, a fection of which is given in the firit of the Author's plates.

whereas

whereas this fubftance, which is as uniform as any vitrified matter of this kind can be fuppofed to be, neither contains minerals, nor figured ftones, nor has any adventitious bodies enveloped in it. Neither does it univerfally prevail, as the limeftone ftrata; nor is it, like them, equally thick; but in fome inftances varies in thieknefs from fix feet to fix hundred.'

Another circumftance that feems to prove it a volcanic production is, that a firatum of clay lying under it, has been found in various places, exhibiting the appearance of having been burnt, as much as an earthen pot or brick. On a comparison, no fenfible difference could be obferved between this clay, and another portion of clay in a mine at Heyner common, which had been burnt by a firatum of coal having been on fire underneath it. On this occafion the Author offers fome probable conjectures, to explain in what manner this lava was introduced between fuch immenfe ftrata of ftone; and why it did not force its way through the surface of the earth, according to the usual courfe of volcanic operations.

In this Appendix the Author makes a general and important remark, founded on the refult of his obfervations made not only in Derbyshire, but in Staffordshire, Shropshire, &c. It relates to the difference of fituation between the marine or animal exuvia, and the impreffions of vegetables. The fuperior or clayey ftrata, contain the vegetable impreffions, but exhibit no marine productions whatever: whereas the inferior or lime ftone frata, contain the exuviæ of marine animals, and no vegetable forms. whatever. These circumftances, according to him, indicate the order in which the refpective firata were fucceffively arranged. The inferior lime ftone firata, containing marine productions only, must have been conftituted while the fea covered the earth: the fuperior, exhibiting impreffions of vegetables, must have been formed after that earth became habitable.

Some exceptions, however, to this arrangement are to be met with in Authors; particularly one, which Mr. W. quotes from Ray, that apparently contradicts the general order': but thefe he confiders only as anomalies, occafioned by partial or local revolutions. In Derbyshire, one inftance only feems, at firstfight, to contradict his general rule. Numerous exuvia of shell fish have been found in the fuperior ftrata, incumbent on limeftone: but on examination it appears that these shells are not marine productions, but of fresh water lakes, rivers, &c.; in fhort, they are the remains of horse mufcles.

We cannot terminate our account of this performance without taking notice of a very extraordinary_phenomenon, that has frequently been obferved in fome of the Derbyshire mines here named; where the vein of ore is divided into two equal parts,

parallel

parallel to the fides of a fiffure, refembling two flabs of marble, whofe furfaces, which have a high natural polish, are in contact with each other, though without the leaft degree of cohefion. The fingular circumftance relating to them is thus defcribed.

If a fharp pointed pick is drawn down the vein with a fmall degree of force, the minerals begin to crackle, as fulphur excited to become electrical by rubbing; after this, in the fpace of two or three minutes, the folid mafs of the minerals explodes with much violence, and the fragments fly out, as if blafted with gun-powder.

Thefe effects have frequently happened, by which many workmen have been much wounded, but none killed, both in the Eyam mines and in that at Castleton.

In the year 1738 a prodigious explosion happened in the mine called Haycliff.

The quantity of two hundred barrels of the above minerals were blown out at one blaft; each barrel, I prefume, contained no less than three or four hundred weight.

At the fame time a man was blown twelve fathoms perpendicular, and lodged upon a floor, or bunding, as the miners call it.

When the above explofion happened, the barrel, or tub, in which the minerals, &c. are raifed to the furface, happened to hang over the engine-shaft, which is nearly seven feet wide, and five or fix hundred yards from the forefield, or part, where the explosion happened; this barrel, though of confiderable weight, was lifted up in the hook on which it was fufpended; and the people on the furface felt the ground fhake, as by an earthquake,

Such are the effects which have frequently been produced in all the above mines: but from what cause they proceed I have not yet been able to discover, nor even the leaft traces towards it.

When these wonderful effects firft happened they deterred the workmen for fome years from venturing to work the mines, but afterwards they availed themselves of this extraordinary property. A man would go to the forefield, give a scratch with his pick, and run away; by which means he loofened as much of the minerals as could have been done by common workmanship with ten men in three months.

Thefe curious obfervations I received from Mr. Mettam of Eyam,. overfeer of the mines, who alfo addreffed the following account of them to Mr. George Tiffington of Winster.

" SIR,

Eyam, 2 July, 1769.

"I fend you, by the bearer, two fpecimens of our flickenfides' containing all the variety of minerals where the explofions happen ; they fly out in fuch flappits †, smooth on one fide. The explosions are fometimes heard to the furface, and felt like an earthquake; they frequently blow out all the candles in the mine, and fplit the ftemples into fplinters as fmall as the twigs of a birch beefom, to *Slickenfides, fhining, as if polished by art, on one fide.

Slappits, fragments of the minerals burft out of the vein. Stemples, joints laid across fiffures, when the minerals are cut out, by way of making a floor, on which rubbish is depofited, to fave the expence of railing it to the furface.

the