A Source Book in Geology [1400-1900]

Author: Nicolaus Steno  | Date: 1916

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From The Prodromus of Nicolaus Steno’s Dissertation concerning a Solid Body Enclosed by Process of Nature within a Solid, translated into English by John Garrett Winter, The Macmillan Company, New York, 1916.

The Problem of the Fossils

Do not be surprised, therefore, Most Serene Prince, if, for a whole year’s time, and, what is more, almost daily, I have said that the investigation for which the teeth of the shark had furnished an opportunity, was very near an end. For having once or twice seen regions where shells and other similar deposits of the sea are dug up, when I observed that those lands were sediments of the turbid sea and that an estimate could be formed of how often the sea had been turbid in each place, I not only over-hastily fancied, but also dauntlessly informed others, that a complete investigation on the spot was the work of a very short time. But thereafter, while I was examining more carefully the details of both places and bodies, these day by day presented points of doubt to me as they followed one another in indissoluble connection, so that I saw myself again and again brought back to the starting-place, as it were, when I thought I was nearest the goal. I might compare those doubts to the heads of the Lernean Hydra, since when one of them had been got rid of, numberless others were born; at any rate, I saw that I was wandering about in a sort of labyrinth, where the nearer one approaches the exit, the wider circuits does one tread.


The Dissertation itself I had divided into four parts, of which the first, taking the place of an introduction, shows that the inquiry concerning sea objects found at a distance from the sea, is old, delightful, and useful; but that its true solution, less doubtful in the earliest times, in the ages immediately following was rendered exceedingly uncertain. Then after setting forth the reasons why later thinkers abandoned the belief of the ancients, and why, although one may read a great many excellent works by many authors, the question at issue has hitherto been settled by no one anew, I show, returning at length to you, that besides very many other things which under your auspices have in part been recently discovered, and in part freed from old doubts, to you is due our trust that the finishing touch shall soon be put upon this investigation also.


He, therefore, who attributes to Nature the production of any thing, names the universal agent which appears in the production of all things; he who calls the sun to share, limits that agent a little more; he who names the soul or the particular form, mentions a more limited cause than the rest: but one who nevertheless duly weighs the answers of all, finds nothing known, seeing that Nature, the sun’s rays, the soul, and the particular form, are things known only by name. But since, besides the agent, matter and place ought to be taken account of in the production of substances, it is clear that the answer ("produced by Nature") is not only more unknown than the very thing under investigation, but altogether incomplete; as, for example, mollusks found in the earth are said to have been produced by Nature, since those that grow in the sea are also Nature’s work. Nature indeed produces all things, seeing that the penetrating fluid has a place in the production of all things; but one may also say with truth that Nature produces nothing, since that fluid by itself accomplishes nothing; its determination depends upon the place and the matter to be moved. We find an illustration in man: he can produce anything if all the necessary things are at hand, but if they are wanting, can produce nothing.


If a solid body is enclosed on all sides by another solid body, of the two bodies that one first became hard which, in the mutual contact, expresses on its own surface the properties of the other surface.* Hence it follows:

1. That in the case of those solids, whether of earth, or rock, which enclose on all sides and contain crystals, selenites, marcasites, plants and their parts, bones and the shells of animals, and other bodies of this kind which are possessed of a smooth surface, these same bodies had already become hard at the time when the matter of the earth and rock containing them was still fluid. And not only did the earth and rock not produce the bodies contained in them, but they did not even exist as such when those bodies were produced in them.

2. That if a crystal is enclosed in part by a crystal, a selenite by a selenite, a marcasite by a marcasite, those contained bodies had already become hard when a part of the containing bodies was still fluid.


If a solid substance is in every way like another solid substance, not only as regards the conditions of surface, but also as regards the inner arrangement of parts and particles, it will also be like it as regards the manner and place of production, if you except those conditions of place which are found time and again in some place to furnish neither any advantage nor disadvantage to the production of the body. Whence it follows:

1. That the strata of the earth, as regards the place and manner of production, agree with those strata which turbid water deposits.

2. That the crystals of mountains, as regards the manner and place of production, agree with the crystals of niter, although it is not therefore essential that the fluid in which they were produced should have been aqueous.

3. That those bodies which are dug from the earth and which are in every way like the parts of plants and animals, were produced in precisely the same manner and place as the parts of the plants and the animals were themselves produced.


What has been said concerning shells must also be said concerning other parts of animals, and animals themselves buried in the earth. Here belong the teeth of sharks, the teeth of the eagle-fish, the vertebrae of fishes, whole fish of every kind, the crania, horns, teeth, femurs, and other bones of land animals; since all these are either wholly like true parts of animals, or differ from them only in weight and color, or have nothing in common with them except the outer shape alone.

A great difficulty is caused by the countless number of teeth which every year are carried away from the island of Malta; for hardly a single ship touches there without bringing back with it some proofs of that marvel. But I find no other answer to this difficulty than:

1. That there are six hundred and more teeth to each shark, and all the while the sharks live new teeth seem to be growing.

2. That the sea, driven by winds, is wont to thrust the bodies in its path toward some one place and to heap them up there.

3. That sharks come in shoals and so the teeth of many sharks can be left in the same place.

4. That in lumps of earth brought here from Malta, Besides different teeth of different sharks, various mollusks are also found, so that even if the number of teeth favors attributing their production to the earth, yet the structure of these same teeth, the abundance in each animal, the earth resembling the bottom of the sea, and the other sea objects found in the same place, all alike support the opposite view.

Others find great difficulty in the size of the femurs, crania, and teeth, and other bones, which are dug from the earth. But the objection, that an extraordinary size makes it necessary to conclude the size to be beyond the powers of Nature, is not of so great moment, seeing that:

1. In our own time bodies of men of exceedingly tall stature have been seen.

2. It is certain that men of unnatural size existed at one time.

3. The bones of other animals are often thought to be human bones.

4. To ascribe to Nature the production of truly fibrous bones is the same as saying that Nature can produce a man’s hand without the rest of the man.

There are those to whom the great length of time seems to destroy the force of the remaining arguments, since the recollection of no age affirms that floods rose to the place where many marine objects are found to-day, if you exclude the universal deluge, four thousand years, more or less, before our time. Nor does it seem in accord with reason that a part of an animal’s body could withstand the ravages of so many years, since we see that the same bodies are often destroyed completely in the space of a few years. But this doubt is easily answered, since the result depends wholly upon the diversity of soil; for I have seen strata of a certain kind of clay which by the thinness of their fluid decomposed all the bodies enclosed within them. I have noticed many other sandy i strata which preserved whole all that was entrusted to them. And by this test it might be possible to come to a knowledge of that fluid which disintegrates solid bodies.

The Strata of the Earth

The strata of the earth are due to the deposits of a fluid:

1. Because the comminuted matter of the strata could not have been reduced to that form unless, having been mixed with some fluid and then failing from its own weight, it had been spread out by the movement of the same superincumbent fluid.

2. Because the larger bodies contained in these same strata obey, for the most part, the laws of gravity, not only with respect to the position of any substance by itself, but also with respect to the relative position of different bodies to each other.

3. Because the comminuted matter of the strata has so adjusted itself to the bodies contained in it that it has not only filled all the smallest cavities of the contained body, but has also expressed the smoothness and lustre of the body in that part of its own surface where it is in contact with the body, although the roughness of the comminuted matter by no means admits of similar smoothness and lustre.

Sediments, moreover; are formed so long as the contents in a fluid fail to the bottom of their own weight, whether the said contents have been carried thither from some other where, or have been secreted gradually from the particles of the fluid, that too, either in the upper surface, or equally from all the particles of the fluid.


Concerning the matter of the strata the following can be affirmed:

1. If all the particles in a stony stratum are seen to be of the same character, and fine, it can in no wise be denied that this stratum was produced at the time of the creation from a fluid which at that time covered all things; and Descartes also accounts for the origin of the earth’s strata in this way.

2. If in a certain stratum the fragments of another stratum, or the parts of animals and plants are found, it is certain that the said stratum must not be reckoned among the strata which settled down from the first fluid at the time of the creation.

3. If in a certain stratum we discover traces of salt of the sea, the remains of marine animals, the timbers of ships, and a substance similar to the bottom of the sea, it is certain that the sea was at one time in that place, whatever be the way it came there, whether by an overflow of its own or by the upheaval of mountains.

4. If in a certain stratum we find a great abundance of rush, grass, pine cones, trunks and branches of trees, and similar objects, we rightly surmise that this matter was swept thither by the flooding of a river, or the inflowing of a torrent.

5. If in a certain stratum pieces of charcoal, ashes, pumicestone, bitumen, and calcined matter appear, it is certain that a fire occurred in the neighborhood of the fluid; the more so if the entire stratum is composed throughout of ash and charcoal, such as I have seen outside the city of Rome, where the material for burnt bricks is dug.

6. If the matter of all the strata in the same place be the same, it is certain that that fluid did not take in fluids of a different character flowing in from different places at different times.

7. If in the same place the matter of the strata be different, either fluids of a different kind streamed in thither from different places at different times (whether a change of winds or an unusually violent downpour of rains in certain localities be the cause) or the matter in the same sediment was of varying gravity, so that first the heavier particles, then the lighter, sought the bottom. And a succession of storms might have given rise to this diversity, especially in places where a like diversity of soil is seen.


Concerning the position of strata, the following can be considered as certain:

1. At the time when a given stratum was being formed, there was beneath it another substance which prevented the farther descent of the comminuted matter; and so at the time when the lowest stratum was being formed either another solid substance was beneath it, or if some fluid existed there, then it was not only of a different character from the upper fluid, but also heavier than the solid sediment of the upper fluid.

2. At the time when one of the upper strata was being formed, the lower stratum had already gained the consistency of a solid.

3. At the time when any given stratum was being formed it was either encompassed on its sides by another solid substance, or it covered the entire spherical surface of the earth. Hence it follows that in whatever place the bared sides of the strata are seen, either a continuation of the same strata must be sought, or another solid substance must be found which kept the matter of the strata from dispersion.

4. At the time when any given stratum was being formed, all the matter resting upon it was fluid, and, therefore, at the time when the lowest stratum was being formed, none of the upper strata existed.

As regards form, it is certain that at the time when any given stratum was being produced its lower surface, as also its lateral surfaces, corresponded to the surfaces of the lower substance and lateral substances, but that the upper surface was parallel to the horizon, so far as possible; and that all strata, therefore, except the lowest, were bounded by two planes parallel to the horizon. Hence it follows that strata either perpendicular to the horizon or inclined toward it, were at one time parallel to the horizon.


Hence it could be easily shown:

1. That all present mountains did not exist from the beginning of things.

2. That there is no growing [vegetatio] of mountains.

3. That the rocks of mountains have nothing in common with the bones of animals except a certain resemblance in hardness, since they agree in neither matter nor manner of production, nor in composition, nor in function, if one may be permitted to affirm aught about a subject otherwise so little known as are the functions of things.

4. That the extension of crests of mountains, or chains, as some prefer to call them, along the lines of certain definite zones of the earth, accords with neither reason nor experience.

5. That mountains can be overthrown, and fields carried over from one side of a high road across to the other; that peaks of mountains can be raised and lowered, that the earth can be opened and dosed again, and that other things of this kind occur which those who in their reading of history wish to escape the name of credulous, consider myths.

The Shape and Growth of Crystals

A crystal consists of two hexagonal pyramids and an intermediate prism likewise hexagonal. I call those angles the terminal solid angles which form the apexes of the pyramids, but those angles the intermediate solid angles which are formed by the union of the pyramids with the prism. In the same way I call the planes of the pyramids terminal planes, and the planes of the prism the intermediate planes. The plane of the base is the section perpendicular to all the intermediate planes; the plane of the axis is a section in which lies the axis of the crystal, which consists of the axes of the pyramids and the axis of the prism.

The place where the first hardening of a crystal begins, whether it be between a fluid and a fluid, or between a fluid and a solid, or even in a fluid itself, may remain in doubt; but the place in which the crystal grows after it has already begun to form, is a solid in that part where the crystal is supported on it, whether the place be a stone or another crystal already formed.


The following propositions will show what can be determined concerning the place of the crystal to which new crystalline matter is being added:


A crystal grows while new crystalline matter is being added to the external planes of the crystal already formed. No room at all is here left for the belief of those who affirm that crystals grow, plantlike, by nourishment, and that they draw their nourishment on the side where they are attached to the matrix, and that the particles thus received from the fluid of the rock, and transmitted into the fluid of the crystal, are inwardly added to the particles of the crystal.


This new crystalline matter is not added to all the planes but, for the most part, to the planes of the apex only, or to the terminal planes, with the result:

1. That the intermediate planes, or the quadrilateral planes, are formed by the bases of the terminal planes, and hence the intermediate planes are larger in some crystals, smaller in others, and wholly wanting in still others.

2. That the intermediate planes are almost always striated, while the terminal planes retain traces of the matter added to them.


The crystalline matter is not added to all the terminal planes at the same time, nor in the same amount. Hence it comes to pass:

1. That the axis of the pyramids does not always continue the same straight line with the axis of the prism.

2. That the terminal faces are rarely of a size, whence follows an inequality of the intermediate planes.

3. That the terminal faces are not always triangular, just as all the intermediate planes are not always quadrilateral.

4. That the terminal solid angle is broken up into several solid angles, this being the case frequently also with the solid intermediate angles.


An entire plane is not always covered by crystalline matter, but exposed places are left sometimes toward the angles, sometimes toward the sides, and sometimes in the centre of the plane. Hence it happens:

1. That the same plane, commonly so-called, does not have all its parts located in the same plane, but in different planes extending above it in different ways.

2. That a plane, commonly so-called, in many places is seen to be not a plane but a protuberance.

3. That in the intermediate planes inequalities rise like the steps of stairs.


The crystalline matter added to planes upon the same planes is spread out by the enveloping fluid, and gradually hardens, with the result:

1. That the surface of the crystal comes forth the smoother the more slowly the added matter has hardened, and is left wholly rough if the said matter has hardened before it has spread sufficiently.

2. That the manner in which the crystalline matter is added to the crystal can be distinguished, since where it has hardened suddenly, it reveals a surface full of small tubercles like variolar postules, as it were, just as small drops of oily fluid are wont to float upon an aqueous fluid; sometimes it shows also trilateral and depressed pyramids, if it has hardened somewhat more slowly. The tortuous fringes of the descending matter show now the place to which the fluid matter was being added, now the place toward which it was being advanced, now the arrangement of the matter added, that is, which came first, and which last. And in this way certain roughnesses always appear in the crystals of mountains, nor have I ever seen a crystal whose still unbroken surfaces possess the lustre which the rent sides of the same crystal show after it has been broken, however prolix writers on subjects relating to nature become in extolling the lustre of the crystal which is extracted from the mountains.

FIG. 4.—Figures 1 to 13 on the plate of illustrations accompanying Steno’s Prodromus, 1671.

Explication of the Figures

Quoted verbatim from the "H. O. version" of the Prodromus, translated by Henry Oldenburg and published in London between 1671 and 1673.

The thirteen first figures, designed to explain the Angular Bodies of Chrystal, are reducible to two Classes;

The first contains seven differences of a Plane, in which is the Axis of the Chrystal. In the 1t., 2d. and 3d, the axes of the parts, out of which the body of the Chrystal is composed, do constitute one straight line, but by an intermediate column, which in the 1st figure is wanting, but is seen shorter in the 2d, and longer in the 3d. In the 4th figure the axes of the parts constituting the body of the Chrystal, do not make one straight line. The 5th and 6th figure are of the kind of those, of which I could have produced innumerable, to evince, that in the Plane of the axe, both the number and length of the sides are variously changed without change in the angles, and that in the very midst of the Chrystal there are left various cavities, & formed various plates. The 7th figure doth shew in the plane of the axe, how from the new Chrystallin matter laid upon the planes of the pyramids, both the number and length of the sides are variously sometimes increased, sometimes lessen’d.

The Second Classis contains six differences of the Basis of a Plane. In the 8th, 9th, 10th, and 11th figures, there are only six sides; yet with this difference, that in the 8th figure all the sides are

FIG. 5.—Figures 20 to 25 on the plate of illustrations accompanying Steno’s Prodromus, 1671.

equal; in the 9th and 11th, not all but only the opposite sides are equal; but in the 10th, all opposite sides are unequal. In the 12th figure, the Plane of the base, which should be hexagonal, contains twelve sides. The 13th figure shews, how, by laying a new Chrystallin matter upon the planes of the Pyramids, sometimes the length of the sides, and the number also are variously changed in the plane of the base, without changing the angles.


The six last figures do both shew, how from the present face of Etruria we may collect the six distinct faces of the same Country, above discoursed of, and serve also for the more easy understanding of the particulars, we have deliver’d concerning the Beds of the Earth. The pricked lines represent the Sandy beds of the Earth, so nominated from their main matter, there being mix’t with them divers both Clayie and stony beds. The other lines represent the Stony beds, likewise so called a potiori, seeing there are Beds found in them that are of a softer substance. . . .

The 25th figure exhibits the perpendicular Plane of Etruria, at the time when the Stony Beds were yet entire, & parallel to the horizon.

The 24th shews the vast cavities, eaten out by the force of Fire and Water, without any breach in the upper Beds.

The 23th represents, how Mountains & Vally’s came to be made by the ruine of the superior Beds.

The 22th, that by the Sea new Beds were made in the said Valleys.

The 21th, that of the new Beds the lower ones were consumed, the uppermost remaining untouch’t.

The 20th, that by the breach of the superior sandy Beds there were produced Hillocks and Vallys.

* Steno probably meant to write "that one first became hard which, in the mutual contact, displays the surface forms characteristic of itself."—EDITORS.


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Chicago: Nicolaus Steno, "Of Solids Naturally Contained Within Solids," A Source Book in Geology [1400-1900], trans. John Garrett Winter in A Source Book in Geology [1400-1900], ed. Kirtley F. Mather and Shirley L. Mason (New York: Hafner Publishing Company, 1939), 33–44. Original Sources, accessed January 20, 2019, http://www.originalsources.com/Document.aspx?DocID=PWMFNQZCPSAQFDC.

MLA: Steno, Nicolaus. "Of Solids Naturally Contained Within Solids." A Source Book in Geology [1400-1900], translted by John Garrett Winter, in A Source Book in Geology [1400-1900], edited by Kirtley F. Mather and Shirley L. Mason, New York, Hafner Publishing Company, 1939, pp. 33–44. Original Sources. 20 Jan. 2019. www.originalsources.com/Document.aspx?DocID=PWMFNQZCPSAQFDC.

Harvard: Steno, N, 'Of Solids Naturally Contained Within Solids' in A Source Book in Geology [1400-1900], trans. . cited in 1939, A Source Book in Geology [1400-1900], ed. , Hafner Publishing Company, New York, pp.33–44. Original Sources, retrieved 20 January 2019, from http://www.originalsources.com/Document.aspx?DocID=PWMFNQZCPSAQFDC.