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other history, is likely, if he will think his were examined microscopically, it would knowledge out to its ultimate results, to show itself to be a more or less distinctly have a truer, and therefore a better, concep- laminated mineral substance, and nothing tion of this wonderful universe, and of more. man's relation to it, than the most learned But the slice of chalk presents a totally student who is deep-read in the records of different appearancewhen placed under

. microscope. The The language of the chalk is not hard to made up of very minute granules; but imlearn, not nearly so hard as Latin, if you bedded in this matrix are innumerable bodonly want to get at the broad features of ies, some smaller and some larger, but, on the story it has to tell; and I propose that a rough average, not more than a hundredth we now set to work to spell that story out of an inch in diameter, having a well-detogether.

fined shape and structure. A cubic inch of We all know that if we “burn" chalk some specimens of chalk may contain hunthe result is quicklime. Chalk, in fact, is dreds of thousands of these bodies, coma compound of carbonic acid gas and lime, pacted together with incalculable millions and when you make it very hot the carbonic of the granules. acid flies away and the lime is left.

The examination of a transparent slice By this method of procedure we see the gives a good notion of the manner in which lime, but we do not see the carbonic acid. the components of the chalk are arranged, If, on the other hand, you were to powder and of their relative proportions. But, by a little chalk, and drop it into a good deal rubbing up some chalk with a brush in waof strong vinegar, there would be a great ter and then pouring off the milky fluid, so bubbling and fizzing, and finally a clear as to obtain sediments of different degrees liquid in which no sign of chalk would ap- of fineness, the granules and the minute pear. Here you see the carbonic acid in the rounded bodies may be pretty well sepabubbles; the lime, dissolved in the vine- rated from one another, and submitted to gar, vanishes from sight. There are a great microscopic examination, either as opaque many other ways of showing that chalk is or as transparent objects. By combining essentially nothing but carbonic acid and the views obtained in these various methquicklime. Chemists enunciate the result ods, each of the rounded bodies may be of all the experiments which prove this, by proved to be a beautifully-constructed calstating that chalk is almost wholly com- careous fabric, made up of a number of posed of " carbonate of lime."

chambers, communicating freely with one It is desirable for us to start from the another. The chambered bodies are of vaknowledge of this fact, though it may not rious forms. One of the commonest is seem to help us very far towards what we something like a badly-grown raspberry, seek. For carbonate of lime is a widely- being formed of a number of nearly globuspread substance, and is met with under lar chambers of different sizes congregated very various conditions. All sorts of lime- together. It is called Globigerina, and stones are composed of more or less pure some specimens of chalk consist of little carbonate of lime. The crust which is often else than Globigerinæ and granules. deposited by waters which have drained Let us fix our attention upon the Globithrough limestone rocks, in the form of gerina. It is the spoor of the game we are what are called stalagmites and stalactites, is tracking. If we can learn what it is and carbonate of lime. Or, to take a more fa- what are the conditions of its existence, we miliar example, the fur on the inside of a shall see our way to the origin and past tea-kettle is carbonate of lime; and, for history of the chalk. anything chemistry tells us to the contrary, A suggestion which may naturally enough the chalk might be a kind of gigantic fur present itself is, that these curious bodies upon the bottom of the earth kettle, which are the result of some process of aggregais kept pretty hot below.

tion which has taken place in the carbonate Let us try another method of making the of lime; that, just as in winter the rime on chalk tell us its own history. To the unas- our windows simulates the most delicate and sisted eye chalk looks simply like a very elegantly arborescent foliage — proving that loose and open kind of stone. But it is the mere mineral, water, may, under cerpossible to grind a slice of chalk down so tain conditions, assume the outward form thin that you can see through it — until it of organic bodies - so this mineral subis thin enough, in fact, to be examined with stance, carbonate of lime, hidden away in any magnifying power that may be thought the bowels of the earth, has taken the shape desirable. A thin slice of the fur of a ket- of these chambered bodies. I am not raistle might be made in the same way. If iting a merely fanciful and unreal objection. Very learned men, in former days, have to the surface. But, however well adapted even entertained the notion that all the such an apparatus might be for rough nauformed things found in rocks are of this tical purposes, scientific accuracy could not nature; and if no such conception is at be expected from the armed lead, and to present held to be admissible, it is because remedy its defects (especially when applied Iong and varied experience has now shown to sounding in great deprhs) Lieut. Brooke, that mineral matter never does assume tht of the American Navy, some years ago inform and strácture we find in fossils. If vented a most ingenious machine, by which any one were to try to persuade you that a considerable portion of the superficial an oyster-shell (which is also chiefly com- layer of the sea-bottom can be scooped out posed of carbonate of lime) had crystal- and brought up, from any depth to which lized out of sea-water, I suppose you would the lead descends. laugh at the absurdity. Your laughter In 1853, Lieut. Brooke obtained mud would be justified by the fact that all ex- from the bottom of the North Atlantic, beperience tends to show that oyster-shells tween Newfoundland and the Azores, at a are formed by the agency of oysters, and depth of more than 10,000 feet, or two in no other way. And if there were no miles, by the help of this sounding apparabetter reasons, we should be justified, on tus. The specimens were sent for examilike grounds, in believing that Globigerina nation to Ehrenberg of Berlin, and to is ot the product of anything but vital ac- Bailey of West Point, and those able mic tivity.

roscopists found that this deep-sea mud was Happily, however, better evidence in almost entirely composed of the skeletons proof of the organic nature of the Globige- of living organisms — the greater proporrince than that of analogy is forthcoming. tion of these being just like the GlobiIt so happens that calcareous skeletons, gerinæ already known to occur in the exactly similar to the Globigerinæ of the chalk. chalk, are being formed, at the present Thus far, the work had been carried on moment, by minute living creatures, which simply in the 'interests of science, but flourish in multitudes, literally more numer- Lieut. Brooke's method of sounding acous than the sands of the sea-shore, over a quired a high commercial value when the large extent of that part of the earth's sur- enterprise of laying down the telegraphface which is covered by the ocean. cable between this country and the United

The history of the discovery of these liv- States was undertaken. For it became a ing Globigerinæ, and of the part which they matter of immense importance to know, play in rock-building, is singular enough. not only the depth of the sea over the It is a discovery which, like others of no whole line along which the cable was to be less scientific importance, has arisen, inci- laid, but the exact nature of the bottom, dentally, out of work devoted to very dif- so as to guard against chances of cutting or ferent and exceedingly practical interests. fraying the strands of that costly rope.

When men first took to the sea they The Admiralty consequently ordered Capspeedily learned to look out for shoals and tain Dayman, an old friend and shipmate rocks, and the more the burthen of their of mine, to ascertain the depth over the ships increased, the more imperatively ne- whole line of the cable, and to bring back cessary it became for sailors to ascertain specimens of the bottom. In former days, with precision the depth of the waters they such a command as this might have soundtraversed. Out of this necessity grew the ed very much like one of the impossible use of the lead and sounding-line; and, ulti- things which the young prince in the Fairy mately, marine-surveying, which is the re- Tales is ordered to do before he can obtain cording of the form of coasts and of the the hand of the princess. However, in the depth of the sea, as ascertained by the months of June and July, 1857, my friend sounding-lead, upon charts.

performed the task assigned to him with At the same time, it became desirable to great expedition and precision, without, so áscertain and to indicate the nature of the far as I know, having met with any reward sea-bottom, since this circumstance greatly of that kind. The specimens of Atlantic affects its goodness as holding ground for mud which he procured were sent to me to • anchors. Some ingenious tar, whose name be examined and reported upon.* deserves a better fate than the oblivion in

See Appendix to Captain Dayman's “ Deep-Sea to which it has fallen, attained this object Soundings in the North Atlantic Ocean, between by “arming” the bottom of the lead with Ireland and Newfoundland, made in H. M. s. Cy.

clops. Published by order of the Lords Commis a lump of grease, to which more or less of stoners of the Admiralty. 1868.” They have since the sand or mud, or broken shells, as the formed the subject of an elaborate Memoir by

Messrs. l’arker and Jones, published in the Philo case might be, adhered, and was brought sophical Transactions for 16u5.

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The result of all these operations is that simplest imaginable description. It is, in we know the contours and nature of the fact, a mere particle of living jelly, withsurface-soil covered by the North Atlantic out defined parts of any kind — without a for a distance of 1,700 miles from east to mouth, nerves, muscles, or distinct organs, west, is well as we know that of any part and only manifesting its vitality to ordinaof the dry land.

ry observation by thrusting out and reIt is a prodigious plain — one of the wid- tracting, from all parts of its surface, long est and most ever plains in the world. If filamentous processes, which serve for arms the sea were drained off, you might drive a and legs. Yet this amorphous particle, wagon all the way from Valentia, on the devoid of everything which in the higher west coast of Ireland, to Trinity Bay, in animals we call organs, is capable of feedNewfoundland. And, except upon

one ing, growing, and multiplying; of separatsharp incline about 200 miles from Valen- ing from the ocean the small proportion of tia, I am not quite sure that it would even carbonate of lime which is dissolved in seabe necessary to put the skid on, so gentle water; and of building up that substance are the ascents and descents upon that into a skeleton for itself, according to a long route. From Valentia the road would pattern which can be imitated by no other lie down hill about 200 miles to the point known agency. at which the bottom is now covered by The notion that animals can live and 1,700 fathoms of sea-water. Then would flourish in the sea at the vast depths from come the central plain, more than a thou- which apparently living Globigerinæ have sand miles wide, the inequalities of the sur- been brought up, does not agree very well face of which would be hardly perceptible, with our usual conceptions respecting the though the depth of water upon it now va- conditions of animal life; and it is not so ries from 10,000 to 15,000 fect; and there absolutely impossible as it might at first are places in which Mont Blanc might be sight appear to be, that the Globigerinæ of sunk without showing its peak above water. the Atlantic sea-bottom do not live and die Beyond this, the ascent on the American where they are found. side commences, and gradually leads, for As I have mentioned, the soundings from about 300 miles, to the Newfoundland the great Atlantic plain are almost enshore.

tirely made up of Globigerinæ, with the Almost the whole of the bottom of this granules which have been mentioned and central plain (which extends for many hun- some few other calcareous shells; but a dred miles in a north and south direction) small percentage of the chalky mud - peris covered by a fine mud, which, when haps at most some five per cent. of it - is brought to the surface, dries into a grayish- of a different nature, and consists of shells white friable substance. You can write and skeletons composed of silex, or pure with this on a blackboard, if you are so in- fint. These silicious bodies belong partclined, and to the eye it is quite like very ly to those lowly vegetable organisms soft, greyish chalk. Examined chemical- which are called Diatomaceve, and partly to ly, it proves to be composed almost wholly those minute and extremely simple animals of carbonate of lime; and if you make a termed Radiolariæ. It is quite certain section of it in the same way as that of the that these creatures do not live at the botpiece of chalk was made, and view it with tom of the ocean, but at its surface the microscope, it presents innumerable where they may be obtained in prodigious Globigerinæ, embedded in a granular ma- numbers by the use of a properly contrix.

structed net. Hence it follows that these Thus this deep-sea mud is substantially silicious organisms, though they are not chalk. I say substantially, because there heavier than the very lightest dust, must are a good many minor differences: but have fallen in some cases through fifteen as these have no bearing upon the ques- thousand feet of water, before they reached tion immediately before us, which is the their final resting-place on the ocean floor. nature of the Globigerine of the chalk - it And, considering how large a surface these is unnecessary to speak of them. bodies expose in proportion to their weight,

Globigerince of every size, from the it is probable that they occupy a great smallest to the largest, are associated to-length of time in making their burial jour- • gether in the Atlantic mud, and the cham-ney from the surface of the Atlantic to the bers of many are filled by a soft animal bottom. matter. This soft substance is, in fact, the But if the Radiolarice and Diatoms are remains of the creature to which the Globi- thus rained upon the bottom of the sea from gerina shell, or rather skeleton, owes its ex- the superficial layer of its waters in which istence — and which is an animal of the they pass their lives, it is obviously possi

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ble that the Globigerinæ may be similarly and problematical, were peculiar to the Atderived; and if they were so, it would be lantic soundings. much more easy to understand how they ob- But, a few years ago, Mr. Sorby, in maktain their supply of food than it is at present. ing a careful examination of the chalk by Nevertheless, the positive and negative evi- means of thin sections and otherwise, obdence all points the other way. The skele- served, as Ehrenberg had done before him, tons of the full-grown, deep-sea Globigerince that much of its granular basis possesses a are so remarkably solid and heavy in pro- definite form. Comparing these formed parportion to their surface as to seem little ticles with those in the Atlantic soundings, fitted for floating, and, as a matter of fact, be found the two to be identical; and thus they are not to be found along with the Dia- proved that the chalk, like the soundings, toms and Radiolariæ in the uppermost stra- contains these mysterious coccoliths and coctum of the open ocean.

cospheres. Here was a further and a most It has been observed, again, that the abun- interesting confirmation, from internal evidance of Globigerinæ, in proportion to other dence, of the essential identity of the chalk organisms of like kind, increases with the with modern deep-sea mud. Globigerino, depth of the sea; and that deep-water Glo- coccoliths, and coccospheres are found as the bigerinæ are larger than those which live in chief constituents of both, and testify to the shallower parts of the sea; and such facts general similarity of the conditions under negative the supposition that these organ- which both have been formed. * isms have been swept by currents from the The evidence furnished by the hewing, shallows into the deeps of the Atlantic. facing, and superposition of the stones of

It therefore seems to be hardly doubtful the Pyramids that these structures were that these wonderful creatures live and die built by men, has no greater weight than at the depths in which they are found.* the evidence that the chalk was built by

However, the important points for us are Globigerinæ ; and the belief that those anthat the living Globigerinæ are exclusively cient Pyramid-builders were terrestrial and marine animals, the skeletons of which air-breathing creatures like ourselves, is not abound at the bottom of deep seas; and better based than the conviction that the that there is not a shadow of reason for chalk-makers lived in the sea. believing that the babits of the Globigerinæ But as our belief in the building of the of the chalk differed from those of the ex- Pyramids by men is not only grounded on isting species. But if this be true, there is the internal evidence afforded by these no escaping the conclusion that the chalk it- structures, but gathers strength from mulself is the dried mud of an ancient deep sea. titudinous collateral proofs, and is clinched

In working over the soundings collected by the total absence of any reason for a by Captain Dayman, I was surprised to find contrary belief; so the evidence drawn from that many of what I have called the “ gran- the Globigerine that the chalk is an ancient ules" of that mud, were not, as one might sea-bottom, is fortified by innumerable inhave been tempted to think at first, the mere dependent lines of evidence; and our belief powder and waste of Globigerince, but that in the truth of the conclusion to wbich all they had a definite form and size. I termed positive testimony tends, receives the like these bodies “coccoliths,” and doubted their negative justification from the fact that no organic nature. Dr. Wallich verified my other hypothesis has a shadow of foundaobservation, and added the interesting dis- tion. covery that not unfrequently bodies similar It may be worth while briefly to consider to these “coccoliths" were aggregated to- a few of these collateral proofs that the gether into spheroids, which he termed “coc- chalk was deposited at the bottom of the cospheres." So far as we knew, these bodies, sea. the nature of which is extremely puzzling The great mass of the chalk is composed, hard parts in the mud, just as the oysters | urchins, which would be detached by the die and leave their shells behind them in smallest jar, often remain in their places. the mud of the present seas.

* During the cruise of H. M. S. Bull-Dog, com- as we have seen, of the skeletons of Globimanded by Sir Leopold M'Clintock, in 1860, living gerina, and other simple organisms, imstar-fish were brought up, clinging to the lowest bedded in granular matter. Here and there, part of the sounding line, from a depth of 1,200 fathoms, midway between Cape Farewell, in Green. however, this hardened mud of the ancient land, and the Rockall banks.

sea reveals the remains of higher animals tained that the sea bottom at this point consisted of the ordinary Globigerina ooze, and that the stom- which have lived and died, and left their achs of the star-tishes were full of Globigerinæ. This discovery removes all objections to the existence of * I have recently traced out the development of living Globigerinæ at great depths, which are based the “coccoliths" from a diameter of one seven-thouupon the supposed diinculty of maintaining animal sandth of an inch up to their largest size (which is lite under such conditions; and it throws the burden about one sixteen-hundredth), and no longer doubt of proof upon those who object to the supposition that they are produced by independent organisms, that the Globigerina live and die where they are which, like the Globigerino, live and die at the found.

Dr. Wallich Ascer

bottom of the sea.

In a word, it is certain that these animals There are certain groups of animals at have lived and died when the place which the present day which are never found in they now occupy was the surface of as much. fresh waters, being unable to live anywhere of the chalk as had then been deposited; but in the sea. Such are the corals; those and that each has been covered up by the corallines which are called Polyzoa; those layer of Globigerina mud, upon which the creatures which fabricate the lamp-shells, creatures imbedded a little higher up have and are called Brachiopoda ; the pearly in like manner lived and died. But some of Nautilus, and all animals allied to it; and these remain3 prove the existence of repall the forms of sea-urchins and star-fishes. tiles of vast size in the chalk sea. These

Not only are all these creatures confined lived their time, and had their ancestors to salt water at the present day; but, so and descendants, which assuredly implies far as our records of the past go, the con- time, reptiles being of slow growth. ditions of their existence have been the There is more curious evidence, again, same: hence their occurrence in any de- that the process of covering up, or, in other posit is as strong evidence as can be ob- words, the deposit of Globigerina skeletons, tained that that deposit was formed in the did not go on very fast. It is demonstrasea. Now the remains of animals of all the ble that an animal of the cretaceous sea kinds which have been enumerated, occur might die, that its skeleton might lie unin the chalk, in greater or less abundance; covered upon the sea-bottom long enough while not one of those forms of shell-fish to lose all its outward coverings and appenwhich are characteristic of fresh water bas dages by putrefaction; and that, after this yet been observed in it.

Lad happened, another animal might attach When we consider that the remains of itself to the dead and naked skeleton, more than three thousand distinct species might grow to maturity, and might itself die of aquatic animals have been discovered before the calcareous mud had buried the among the fossils of the chalk, that the whole. great majority of them are of such forms as Cases of this kind are admirably deare now met with only in the sea, and that scribed by Sir Charles Lyell. He speaks there is no reason to believe that any one of the frequency with which geologists find of them inhabited fresh water — the collat- in the chalk a fossilized sea-urchin, to which eral evidence that the chalk represents an is attached the lower valve of a Crania. ancient sea-bottom acquires as great force This is a kind of shell-fish, with a shell comas the proof derived from the nature of the posed of two pieces, of which, as in the oyschalk itself. I think you will now allow ter, one is fixed and the other free. that I did not overstate my case when I as- “ The upper valve is almost invariably serted that we have as strong grounds for wanting, though occasionally found in a believing that all the vast area of dry land, perfect state of preservation in the white at present occupied by the chalk, was once chalk at some distance. In this case, we at the bottom of the sea, as we have for any see clearly that the sea-urehin first lived matter of history whatever; while there is from youth to age, then died and lost its no justification for any other belief. spines, which were carried away. Then the

No less certain is it that the time during young Crania adhered to the bared shell, which the countries we now call south-east grew and perished in its turn; after which, England, France, Germany, Poland, Russia, the upper valve was separated from the Egypt, Arabia, Syria, were more or less lower, before the Echinus became envelcompletely covered by a deep sea, was of oped in chalky mud."* considerable duration.

A specimen in the Museum of Practical We have already seen that the chalk is, Geology, in London, still further prolongs in places, more than a thousand feet thick. the period which must have elapsed between I think you will agree with me, that it must the death of the sea-urchin and its burial have taken some time for the skeletons of by the Globigerinæ. For the outward face animalculæ of a hundredth of an inch in di- of a Crania, which is attached to a seaameter to heap up such a mass as that. I urchin (Micraster), is itself overrun by an have said that throughout the thickness of incrusting coralline, which spreads thence the chalk the remains of other animals are over more or less of the surface of the seascattered. These remains are often in the urchin. It follows that, after the upper most exquisite state of preservation. The valve of the Crania fell off, the surface of valves of the shell-fishes are commonly adberent; the long spines of some of the sea- Bart., F.R.S., p. 23.

• "Elements of Geology," by Sir Charles Lyell, 428

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LIVIXG AGE.

VOL. XI.

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