NAUTILUS. (FOSSIL.) HORIZONTAL.
AM. HETEROPHYLLUS. LIAS.
NAUTILUS (FOSSIL), SHOWING THE SIPHUNCLE.
The shell of the ammonite is a continued arch, having transverse arches or ribs crossing the main arch, giving to some particular forms of beauty, and to all the peculiar symmetry of a series of spiral curves. But, to compensate for the thinness of the shell, a peculiar adaptation is provided; it consists in the flutings which are seen in the surface, occasioned by the transverse ribs. A pencil-case made of a thin plate of silver is all the stronger for being fluted, and the zinc roof of a railway station is fluted or corrugated, on the same principle. It is thus that strength is combined with economy of material and elegance of form. In the ammonite we see this recent invention anticipated by the Creator, long ages ere man had appeared. In addition to this, those round knobs or bosses studding some of the ammonites (e.g. 1 and 3), like gems upon a diadem, add strength as well as beauty to their frail forms, and thus served the same purpose as the groin work in gothic architecture, a beautiful illustration of which may be seen in the roof of Salisbury Cathedral. Then, looking at the chambers of the shell in the sections, we find that some were for living in, while others were mere empty air-cells, used for purposes of elevation or depression, according as the animal wished to rise to the top or sink to the bottom of the sea,—these front chambers being the drawing-rooms in which the aristocratic ammonite lived. Running round them is an hydraulic instrument, called the siphuncle, or air-tube, by means of which singular mechanism this curious animal altered his specific gravity for purposes of sinking or swimming. “The universal prevalence of such delicate contrivances in the siphuncle, and of such undeviating and systematic union of buoyancy and strength in the air chambers throughout this entire family, are amongst the most prominent instances of order and method that pervade these remains of former races that inhabited the ancient seas; and strange indeed must be the construction of that mind, which can believe that all this order and method can have existed without the direction and agency of some commanding and controlling Mind,”[[79]] These are what Cowper finely calls “the unambiguous footsteps of the God;” and in tracing them our minds are elevated into exalted ideas of Him, whose wisdom is unsearchable, and whose ways are past finding out. With regard to the sections of the ammonite, as seen in the two previous figures, dimly indeed compared with the beautiful specimens from which they were copied, we can only add, in the words of the treatise just quoted, “Nothing can be more beautiful than the sinuous windings of these sutures in many species, at their union with the exterior shell, adorning it with a succession of most graceful forms, resembling festoons of foliage and elegant embroidery. When these thin septa are converted into iron pyrites, their edges appear like golden filagree work, meandering amid the pellucid spar that fills the chambers of the shelf.”
We pass by some other fossils found in the lias, such as the pentacrinite, of which we shall speak when we come to other members of the crinoideal family, gryphites,[[80]] of which the gryphea incurva is the most common type, broken portions of which, and sometimes good specimens, may be found in most gravel heaps, their peculiar form having obtained for them the name among the rustics of “devil’s toe-nails;” and belemnites,[[81]] often met with in vast numbers, and known under the name of ladies’ fingers, and thunderbolts; and fossil fish, a few specimens of which are found in the lias.
Passing by these, we next notice the huge Saurians,[[82]] by far the most wondrous vertebrated animals with which either the ancient or modern vestiges of creation have made us acquainted. These saurians, sometimes called Enaliosaurians, (enalios, the sea, and sauros, a lizard,) on account of their peculiar habitat, may all be included in Milton’s description of the leviathan, though it is hard to tell what precise creature our great poet had in his “mind’s eye” at the time of writing this description—one line of which, from having a syllable too much, reads most unrhythmically—for the crocodile does not go so far out to sea as he represents, and if he did, would be hardly likely to go on to the “Norway foam;” nor can he mean the whale, for the whale has no “scaly rind:”—
“That sea beast,
Leviathan, which God of all his works