Fossil fish

“ For instance, the fossil fishes with a heterocercal tail, found below the new red sandstone, down to the lowest deposits, reminds us of the peculiar termination of the vertebral column in all fish embryos of species living in the present period, to whatever family they may belong, indicating a similarity of structure in the oldest representative of this class, with the earliest condition of the germs of those animals in our days. ”

“ We must endeavour to dismiss from our imagination such forms as the salmon and shark as representatives of the fish-tribe, and the lobster and spider of the arthropods, and try to picture the kind of animals living in the seas in the early Devonian and Upper Silurian times, and then we find, to our surprise, that instead of the contrast between fishes and arthropods being so striking as to make any comparison between the two seem an absurdity, the difficulty in the last century, and even now, is to decide in many cases whether a fossil is an arthropod or a fish. ”

“ One reason of the comparative paucity of fossil fishes may be their enormous destruction for food; thus they perish in greater proportion than the other inhabitants of the sea. In the present state of nature, we find very few fishes, or parts of fishes, in the mud of a drained pond, canal, or river; and it is only in particular parts of the sea that the sounding line brings up from the bottom sharks' teeth, hakes' teeth, &c. It is probable, therefore, that only a small proportion of the number of species of fishes, anciently existing, is now to be obtained from the rocks. ”

“ Stromness ought to be the Mecca, the happy hunting-ground, or the Paradise to geologists, for Hugh Miller has said it could furnish more fossil fish than any other geological system in England, Scotland, and Wales, and could supply ichthyolites by the ton, or a ship load of fossilised fish sufficient to supply the museums of the world. ”

“ In the distribution of marine animals at the present day we find that organisms of simple structure are generally more wide-spread and less susceptible to changes in their environment than are the more complex organisms with specialised structures. Hence we find, for instance, a fossil species of the « 17 » Foraminifera may persist unchanged through several geological periods, while a species of fossil fish has in general not only a short range in time but often a restricted geographical extent. ”

“ Thus the fossil fishes of the early formations, which are characterised by their dense integument and enamelled scales, often present the entire forms of the originals, and generally considerable portions of the connected scales, with the fins and other appendages: while the specimens of later deposits, which contain a large proportion of species with delicate scales, more often display the mineralized osseous skeleton, than the dermal structure. Sedimentary strata composed of mud or fine detritus, of whatever age, have been most favourable to the preservation of the entire forms ”

“ The head of one fish, the body of another, decorated with the fins of a third, and perhaps the tail of a fourth, of different species, or even genera, are dove-tailed together, coloured, and varnished, so as to deceive the common observer, and, occasionally, even the experienced collector. Sponging the specimens with cold water will often detect the imposition; for the colour if artificial will be removed, or rendered paler, while the same process will heighten the natural tints. At Pappenheim, Solenhofen, and other places, where fossil crustaceans, as Shrimps, Prawns, &c. ”

“ It results from the review here taken of the history of fossil Fishes, that this important class of vertebrated animals presented its actual gradations of structure amongst the earliest inhabitants of our planet; and has ever performed the same important functions in the general economy of nature, as those discharged by their living representatives in our modern seas, and lakes, and rivers. The great purpose of their existence seems at all times to have been, to fill the waters with the largest possible amount of animal enjoyment. ”

“ If the fossil forms among the mollusks and other shell fish for instance, are not precisely like the modern ones in every respect, they are always classed as separate species, the older forms thus being "extinct," in utter disregard of the striking anatomical differences between the huge Pleistocene mammals and their dwarfish descendants of to-day, which for a hundred years or so were declared positively to be distinct from one another, but are now acknowledged to be identical. ”

“ Agassiz, who, as you know, has become a citizen of the United States, has had the Cuvierian prize awarded to him for his great work on fossil fishes—an honour approved by every lover of science. This distinguished writer says, in his latest publications on fossil zoology, that the number of fossil fishes distributed over the globe is more than 25,000 species; of mammifera, over 3000; reptiles, over 4000; shells, more than 40,000; numbers which greatly exceed all former calculation. ”

“ Not a single species of fossil Fishes has yet been found that is common to any two great geological formations; or living in our present seas. [99]
One important geological result has already attended the researches of M. Agassiz, viz. that the age and place of several formations hitherto unexplained by any other character, have been made clear by a knowledge of the fossil Fishes which they contain. [100]
Sauroid Fishes in the Order Ganoid. ”

“ The fossil remains of fishes rank in the first class of the "Medals of Creation," for they demonstrate the existence of numerous tribes of highly organized beings in some of the most ancient fossiliferous strata, and the continuance of the same type of organization, variously modified, through the entire series of subsequent deposits to the present time. Each geological formation contains peculiar groups of fossil fishes, distinguished by distinct modifications of structure. ”

“ All the ancient fossil fishes belong to the above-mentioned groups, and many of them have little resemblance to existing forms. The Teleostean fishes, which form the great bulk of those now living, cannot be traced back further than the Cretaceous period, while by far the larger number first appear in the Tertiary beds. ”

“ After ages and centuries have passed away, and then after the termination of the Palæozoic period, a change takes place in the formation of the fish tail. “Other ages and centuries pass away, during which the reptile class attains to its fullest development in point of size, organization, and number; and then, after the times of the cretaceous deposits have begun, we find yet another remarkable monstrosity of displacement introduced among all the fishes of one very numerous order, and among no inconsiderable proportion of the fishes of another. ”

“ Fossilization of a Fish.—When a fish dies he leaves no friends. His body is at once attacked by hundreds of creatures ranging from the one-celled protozoa and bacteria to individuals of his own species. His flesh is devoured, his bones are scattered, the gelatinous substance in them decays, and the phosphate of lime is in time dissolved in the water. For this reason few fishes of the millions which die each year leave any trace for future preservation. At the most a few teeth, a fin-spine, or a bone buried in the clay might remain intact or in such condition as to be recognized. ”

“ And again, if it be true that all varieties of fishes and the great whales, and the like, made their appearance on the fifth day, we ought to find the remains of these animals in the older rocks—in those which were deposited before the Carboniferous epoch. Fishes we do find, in considerable number and variety; but the great whales are absent, and the fishes are not such as now live. Not one solitary species of fish now in existence is to be found in the Devonian or Silurian formations. ”

“ Therefore to supply millions of animals with food, and yet not depopulate the watery realms, the issue produced by some of their species is almost incredible. The spawn is not by scores, but by millions: and by this amazing expedient, constant reparation is made proportionable to the immense havoc.
As the different species of fishes are designed to occupy the waters, and range to and fro in that element, so they are wonderfully formed for that purpose. The chief instruments of the motion of a fish are the fins, which in some fishes are more numerous than in others. ”

“ On our own coasts, the marine remains found a few miles from shore, in banks where fish congregate, are different from those found close to the shore, where only littoral species flourish. A large proportion of aquatic creatures have structures that do not admit of fossilization; while of the rest, the great majority are destroyed, when dead, by the various kinds of scavengers that creep among the rocks and weeds. So that no one deposit near our shores can contain anything like a true representation of the fauna of the surrounding sea ”

“ In all these formations we meet with no Mollusca except such as are now alive—with the partial and very limited exception of some of the oldest deposits of this period, in which a few of the shells occasionally belong to species not known to be in existence at the present day. Whilst the Shell-fish of the Quaternary deposits are, generally speaking, identical with existing forms, the Mammals are sometimes referable to living, sometimes to extinct species. ”

“ During the earlier half of the first great period of organic existence, though the polyparia, radiata, articulata, and mollusca, existed, as their remains testified, by myriads, fish had, it was held, not yet entered upon the scene; and the assertors of the development theory founded largely on the presumed fact of their absence. “It is still customary,” says the author of the “Vestiges of Creation,” in his volume of “Explanations,” “to speak of the earliest fauna as one of an elevated kind. When rigidly examined, it is not found to be so. In the first place, it contains no fish. ”

“ Thus fresh waters, the arctic waters, the oceanic abysses are the "back woods" of fish life, localities favorable to the retention of primitive simplicity, equally favorable to subsequent degeneration. Practically all deep-sea fishes are degenerate descendants of shore fishes of various groups. Monotony and isolation permit or encourage degeneration of type. Where the struggle for existence is most intense the higher structures will be retained or developed. Among such facts as these derived from natural selection the cause of the relation of temperature to number of vertebræ must be sought. ”

“ Among land-living forms the amphibians, reptiles, birds, and mammals have been evolved, and have given rise to more than sixty orders.
"The evolution of fishes has been confined to a noteworthy degree within rigid and unshifting bounds; their living medium, with its mechanical effects upon fish-like forms and structures, has for ages been almost constant in its conditions; its changes of temperature and density and currents have rarely been more than of local importance, and have influenced but little the survival of genera and species widely distributed ”

“ The history of any one family of the bony Fishes very closely resembles all the rest—they breathe air and water through the gills. They live by devouring such Fish and the animal life of the great waters as their mouth is capable of admitting. They propagate not by bringing forth their young alive, like the Mammals and a few of the cartilaginous Fishes, nor by distinct eggs, like the remainder of the latter class, but by spawn, as their roe is called, which is made up of hundreds, and in some instances hundreds of thousands of tiny eggs. ”

“ Here will be found hydroids, sea-anemones, starfishes, sea-urchins, barnacles, mussels. In the shallow water, crabs and shrimps are crawling along the sandy bottom or are lying concealed in the mud, while schools of little fishes scoot across the pool. If a fine silk net is drawn through the water and then emptied into a glass dish a whole new world of creatures will be revealed—jellyfishes, ctenophores, hydroids, eggs of fish, tiny copepods, the larvae or young of sea-urchins, starfishes, or oysters. ”

“ As a general rule the various types of animals and plants become simpler in organisation as we descend the geological scale. For example, in the oldest rocks the animals are confined to the groups of Foraminifera, Sponges, Corals, Graptolites, Shell-fish and Trilobites, all back-boneless animals: whilst it was not until the Devonian period that the primitive fishes appeared as a well-defined group ”

“ There are but few natural orders of fishes—and they divide themselves for the purposes of our enquiry chiefly into the Acanthopterygii, or those that possess bony skeletons, with prickly, spinous processes on the dorsal fins, such as the perch, the mullet, and the gurnard; the Malacopterygii, or soft-finned fishes, including the carp, the salmon, &c.; and the Chondropterygii, with cartilaginous spines and bones, embracing such fish as the sturgeon, shark, and skate. ”

“ The ganoids of the second age of vertebrate existence must have congregated as thickly upon that spot in the times of the Lower Old Red Sandstone, as herrings ever do now, in their season, on the best fishing-banks of Caithness or the Moray Firth. I was for some time greatly puzzled in my attempts to restore these ancient fishes, by the peculiarities of their organization. It was in vain I examined every species of fish caught by the fishermen of the place, from the dog-fish and the skate to the herring and the mackerel. ”