Imágenes de página
PDF
ePub

blished beyond the possibility of doubt, by the recent discovery of numerous specimens in the Lias of Lyme Regis,* in which the ink-bags are preserved in a fossil state, still distended, as when they formed parts of the organization of living bodies, and retaining the same juxta-position to an internal rudimentary shell resembling a horny pen, which the ink-bag of the existing Loligo bears to the pen within the body of that animal. (Pl. 28, Fig. 1.)

Having before us the fact of the preservation of this fossil ink, we find a ready explanation of it, in the indestructible nature of the carbon of which it was chiefly composed. Cuvier describes the ink of the recent Cuttle Fish, as being a dense fluid of the consistence of pap, "bouillie," suspended in the cells of a thin net-work that pervades the interior of the ink-bag; it very much resembles common printers' ink. A substance of this nature would readily be transferred to a fossil state, without much diminution of its bulk.†

Pl. 28, Fig. 5, represents an ink-bag of a recent Cuttle Fish, in which the ink is preserved in a desiccated state, being not much diminished from its original volume. Its form is similar to that of many fossil ink-bags (Pl. 29, Figs. 3-10,) and the indurated ink within it differs only from the

* We owe this discovery to the industry and skill of Miss Mary Anning, to whom the scientific world is largely indebted, for having brought to light so many interesting remains of fossil Reptiles from the Lias at Lyme Regis.

+ So completely are the character and qualities of the ink retained in its fossil state, that when, in 1826, I submitted a portion of it to my friend Sir Francis Chantrey, requesting him to try its power as a pigment, and he had prepared a drawing with a triturated portion of this fossil substance; the drawing was shown to a celebrated painter, without any information as to its origin, and he immediately pronounced it to be tinted with sepia of excellent quality, and begged to be informed by what colourman it was prepared. The common sepia used in drawing is from the ink-bag of an oriental species of cuttle-fish. The ink of the cuttle-fishes, in its natural state, is said to be soluble only in water, through which it diffuses itself instanta. neously; being thus remarkably adapted to its peculiar service in the only fluid wherein it is naturally employed.

fossil ink, inasmuch as the latter is impregnated with carbonate of lime.

In a communication to the Geological Society, February 1829, I announced that these fossil ink-bags had been discovered in the Lias at Lyme Regis, in connexion with horny bodies, resembling the pen of a recent Loligo.

These fossil pens are without any trace of nacre, and are composed of a thin, laminated, semi-transparent substance, resembling horn. Their state of preservation is such as to admit of a minute comparison of their internal structure with that of the pen of the recent Loligo; and leads to the same result which we have collected from the examination of so many other examples of fossil organic remains; namely, that although fossil species usually differ from their living representatives, still the same principles of construction have prevailed through every cognate genus, and often also through the entire families under which these genera are comprehended.

The petrified remains of fossil Loligo, therefore, add another link to the chain of argument which we are pursuing, and aid us in connecting successive systems of creation which have followed each other upon our Planet, as parts of one grand and uniform Design. Thus the union of a bag of ink with an organ resembling a pen in the recent Loligo, is a peculiar and striking association of contrivances, affording compensation for the deficiency of an external shell, to an animal much exposed to destruction from its fellowtenants of the deep; we find a similar association of the same organs in the petrified remains of extinct species of the same family, that are preserved in the ancient marl and limestone strata of the Lias. Cuvier drew his figures of the recent Sepia with ink extracted from its own body. I have drawings of the remains of extinct species prepared also with their own ink: with this fossil ink I might record the fact, and explain the causes of its wonderful preservation. I might register the proofs of instantaneous death detected

in these ink-bags, for they contain the fluid which the living sepia emits in the moment of alarm; and might detail farther evidence of their immediate burial, in the retention of the forms of these distended membranes (Pl. 29. Figs. 3 -10;) since they would speedily have decayed, and have spilt their ink, hád they been exposed but a few hours to decomposition in the water. The animals must therefore have died suddenly, and been quickly buried in the sediment that formed the strata, in which their petrified ink and ink-bags are thus preserved. The preservation also of so fragile a substance as the pen of a Loligo, retaining traces even of its minutest fibres of growth, is not much less remarkable than the fossil condition of the ink-bags, and leads to similar conclusions.*

We learn from a recent German publication (Zeiten's Versteinerungen Württembergs. Stuttgart, 1832, Pl. 25 and Pl. 37,) that similar remains of pens and ink-bags are of frequent occurrence in the Lias shale of Aalen and Boll.†

* We have elsewhere applied this line of argument to prove the sudden destruction and burial of the Saurians, whose skeletons we find entire in the same Lias that contains the pens and ink-bags of Loligo. On the other hand, we have proofs of intervals between the depositions of the component strata of the Lias, in the fact, that many beds of this formation have become the repository of Coprolites, dispersed singly and irregularly at intervals far distant from one another, and at a distance from any entire skeletons, of the Saurians, from which they were derived; and in the farther fact, that those surfaces only of the Coprolites, which lay uppermost at the bottom of the sea, have often suffered partial destruction from the action of water before they were covered and protected by the muddy sediment that has afterwards permanently enveloped them. Farther proof of the duration of time, during the intervals of the deposition of the Lias, is found in the innumerable multitudes of the shells of various Mollusks and Conchifers which had time to arrive at maturity, at the bottom of the sea, during the quiescent periods which intervened between the muddy invasions that destroyed, and buried suddenly the creatures inhabiting the waters, at the time and place of their arrival.

† As far as we can judge from the delineations and lines of the structure in Zeiten's plate, our species from Lyme Regis is the same with

Hence it is clear that the same causes which produced these effects during the deposition of the Lias at Lyme Regis, produced similar and nearly contemporaneous effects, in that part of Germany which presents such identity in the character and circumstances of these delicate organic remains.*

Paley has beautifully, and with his usual felicity, de

that which he has designated by the name of Loligo Aalencis; but I have yet seen no structure in English specimens like that of his Loligo Bol lensis.

* Although the resemblance between the pens of the Loligo and a feather (as might be expected from the very different uses to which they are applied) does not extend to their internal structure, we may still, for convenience of description, consider them as composed of the three following parts, which, in all our figures, will be designated by the same letters, A. B. C. First, the external filaments of the plume, (Pl. 28, 29, 30, A.) analogous to those of a common feather. These filaments terminate inwards on a straight line, or base, where they usually form an acute angle with the outer edges of the marginal bands. Secondly, two marginal bands, B. B., dividing the base of the filaments from the body of the shaft; the surface of these bands, B., usually exhibits angular lines of growth in the smaller fossil pens (Pl. 28, Fig. 6, and Pl. 29, Fig. 2,) which become obtuse and vanish into broad curves, in larger specimens, Pl. 29, Fig. 1, and Pl. 30. Thirdly, the broad shaft, which forms the middle of the pen, is divided longitudinally into two equal parts by a straight line, or axis C. it is made up of a number of thin plates, of a horn-like substance, laid on each other, like thin sheets of paper in pasteboard; these thin plates are composed alternately, of longitudinal, and transverse fibres; the former (Pl. 28, Fig. 7. f. f.) straight, and nearly parallel to the axis of the shaft, the latter (Pl. 28, Fig. 7, e. e.) crossing the shaft transversely in a succession of symmetrical and undulating curves. These transverse fibres do not interlace the others, as the woof interlaces the weaver's warp, but are simply laid over, and adhering to them, as in the alternate laminæ of paper made from slices of papyrus; the strength of such paper much exceeds that made from flax or cotton, in which the fibres are disposed irregularly in all directions. The fibres of both kinds are also collected at intervals into fluted fasciculi, Pl. 30, f, and e, forming a succession of grooves and ridges fitted one into another, whereby the entire surface of each plate is locked into the surface of the adjacent plate, in a manner admirably calculated to combine elasticity with strength.

scribed the Unity and Universality of Providential care, as extending from the construction of a ring of two hundred thousand miles diameter, to surround the body of Saturn,. and be suspended, like a magnificent arch, above the heads of his inhabitants, to the concerting and providing an appropriate mechanism for the clasping and reclasping of the filaments in the feather of the Humming-bird. The geologist descries a no less striking assemblage of curious provisions, and delicate mechanisms, extending from the entire circumference of the crust of our planet, to the minutest curl of the smallest fibre in each component lamina of the pen of the fossil Loligo. He finds these pens uniformly associated with the same peculiar defensive provision of an internal ink-bag, which is similarly associated with the pen of the living Loligo in our actual seas; and hence he concludes, that such a union of contrivances, so nicely adjusted to the wants and weaknesses of the creatures in which they occur, could never have resulted from the blindness of chance, but could only have originated in the will and intention of the Creator..

SECTION III.

Proofs of Design in the Mechanism of Fossil Chambered Shells.

NAUTILUS..

I SHALL select from the family of Multilocular, or Cham-bered shells, the few examples which I shall introduce from mineral conchology, with a view of illustrating certain points that have relation to the object of the present Treatise.

I select these, first, because they afford proofs of me

« AnteriorContinuar »