The remains of many other very curious reptiles have been found, particularly some which appear to belong to a gigantic animal of the frog kind, the footmark of which resembles the impression of a human hand; but the remains which have been discovered of these creatures are not sufficiently distinct to give any clear idea of their exact form. There are also two or three kinds of gigantic tortoise.
The bones of several quadrupeds have been discovered, which are now quite extinct. Some of these are of moderate size, such as a species of tapir, and a kind of antelope; but others are enormously large, and one of the most remarkable of these is what is called the Dinotherium, from two Greek words, signifying a fearfully large beast. Of this creature Professor Ansted observes, "It dwelt probably in swamps. Its length was nearly twenty feet; its body huge and barrel-shaped, very much resembling that of the hippopotamus, being little raised above the ground, although the huge columns which formed its legs are supposed to have been nearly ten feet in length. Its head, rarely, perhaps, brought entirely above the water, was like that of a large elephant, and it was provided with a short, but very muscular and powerful proboscis. A pair of large and long tusks were appended to this skull, and curve downwards, as in the walrus." But, it is a most remarkable fact that these tusks do not proceed from the upper jaw, where they would be supported by the bones of the neck, but are fixed in the lower jaw, which they seem to have drawn down in the most uncomfortable manner. "There can scarcely be a doubt," Mr. Ansted observes, "that an animal provided with appendages so placed was an inhabitant of the water, and the tusks, which are very large, were probably useful as pickaxes," enabling the creature to dig for food by day, and perhaps serving as anchors to retain it in a safe place during the night.
Many traces have been found of gigantic birds which have now completely disappeared, particularly of a wingless bird, called the Dinornis, which appears to have been about seventeen feet high. Impressions of the feet of birds, apparently resembling the ostrich, which must have been of enormous size, are also frequently found on sandstone and the lias limestone, in various parts of Great Britain, particularly on the south coast of England, and in the west of Scotland. Specimens of a similar nature are also found on various parts of the Continent.
Impressions of fishes of various kinds have been found, some of which are very distinct, while others are so much decayed, that it is scarcely possible to ascertain what their original form has been. "This condition," observes Mr. Ansted, "is partly owing to the nature of the bed which must have been originally a fine mud, in which the fish had rotted after death, when the bones separating, and the fins becoming detached, the thin fragile scales, unlike the bony enamelled case of the older fishes, would not afford a coating solid enough to preserve the integrity of the form." Many, however, are found sufficiently perfect to be classed; and though many are of species that are still common, others have become extinct. Among the latter is one very curious kind, which has "a fin rising like an immense mast behind the head, to a height far greater than the length of the body."
The most interesting organic remains are, however, those of the zoophytes, and of the crustaceous and molluscous animals. Among the zoophytes the most curious are what are called the Encrinites or Crinoidal animals, because many of them exhibit the appearance of a cup-shaped flower, opening on the top of a stalk; this flower-like shape being comparatively simple in many species, while in others there is a complication in the number of branches stretching out from the principal stalk, and in the multitude of arms and fingers projecting from the aperture of the mouth, which seems quite unrivalled in complexity in any other animal, whether recent or extinct." The Dudley Encrinites or stone lilies, as they are popularly called, are remarkably fine, and of many different kinds. They appear to have been complete zoophytes, growing out of the soft mud in the beds of ponds and rivers, with a root like a plant, the body of an animal, and long arms or feelers; the body and feelers forming what may be considered the flower of the zoophyte. The stalk was composed of numerous rings like vertebrae, which are now often found distinct and in different places. To conceive the appearance of another of these animals, Professor Ansted observes, "we must imagine trunks of trees in the primitive ages of the world floating in the sea, and attached to them in large clusters, like the bunches of barnacles sometimes suspended from a ship's bottom, the singular pentacrinites, their long stony columns fringed thickly with branches of articulated stone, with a strong coat of mail surrounding the pouch or stomach, and a similar but more delicate defence covering the extensile proboscis. With innumerable arms widely extended in a complicated fringe, this strange mass of living stone expanded itself, and drew within its cold embrace the floating bodies on which it fed."
Corals and Madrepores are zoophytes of which very beautiful remains are found in a fossil state. These remains consist of what seem to have been the horny skeletons of animals similar to those which form the corals that are met with at the present day. They were formed like these by an immense multitude of polyps, the whole, as Professor Ansted expresses it, "constituting a kind of compound animal, in which each individual works to increase the general mass, and is affected by that which affects this mass; but each, also, has a separate existence, being provided with a stomach and arms, to obtain and digest food, and capable of being injured or destroyed without the functions of the complete body being at all interfered with."
Among the corallines or small corals, the most beautiful organic remains belong to those called Aulopora and Catenipora. The first, which is simple and flower-like, is common among the oldest fossiliferous rocks, and closely resembles many species which are yet found in the southern and tropical seas. The other kind, which is popularly called the chain coral, is extremely common among the rocks at Dudley and other Silurian localities.
The Trilobites were very curious crustaceous animals. "These," Professor Ansted observes, "were provided with a large semicircular or crescent-shaped shield, completely defending the head; the body was in like manner secured from the attack of an enemy, by a number of plates or segments moving readily upon one another, like the horny plates of a shrimp; and the tail was armed with a similar series. The animal seems not to have had antennae, and to have possessed short and rudimentary legs; but on the head were placed a pair of large conical projections covered with eyes, by the help of which any approaching danger might be seen; and the power of rolling itself into a ball, which it possessed in common with the wood-louse and the chiton, enabled this creature, no doubt, to escape the attack of many of its enemies. It is not very easy either to make out the habits of an animal of such singular organization and of which only the hard external coat is preserved, or to speculate with regard to its food, and its method of obtaining it. From the absence of antennae, however, and the want of powerful extremities, as well as from the manner in which these fossils are found (for they seem to have been very gregarious, living by thousands in a single locality, and often heaped upon one another), the different species probably lived for the most part in shallow water, not buried in mud, but floating near the surface with their under side uppermost, feeding on the minute and perhaps microscopic animalcules that usually abound in such localities. There are several natural groups, marked by differences somewhat considerable, but the number of species is not great. The most remarkable point with regard to these trilobites is the presence of the large compound eyes with which they were provided. These eyes appear to be constructed on the same principle as those of the dragon-fly and other insects: they are ranged round about three-fourths of two conical projections rising one from each side of the head, and they are so placed that the animal, without moving from the spot in which it might be, could see in all directions around it." The trilobites are found in the greatest abundance at Dudley and its vicinity.
Among the shells the most interesting are what are called the Ammonites, or the shell of an animal somewhat similar to the Nautilus, but having a connecting siphon on the outside, instead of within. The Belemnite "has received its name," says Professor Ansted, "from a peculiar dart-shaped stony fossil, and which, under various local names, such as the thunderbolt, &c., is familiar to most people in the different parts of England where it occurs abundantly. It is found varying in size from specimens not an inch long, to others measuring upwards of a foot; but the structure is generally seen to be the same, the fossil when complete being more or less cylindrical, with one conical extremity, the other end widening out and exhibiting a conical hollow, which is sometimes filled up with a number of little cup-shaped bodies like watch-glasses, fitting into one another." Naturalists were long puzzled with regard to this fossil, but its history is now perfectly cleared up by the aid of specimens which not only exhibit all the solid parts in their natural position, but even present to our notice the muscular fibre, very little altered. The whole contour of the animal is, indeed, accurately determined, including the feelers projecting from the head, the fins, the tail, and even a solidified dark fluid once preserved within the body, and intended to serve the living animal as a defence from its enemies, by enabling it to cloud the surrounding water when attacked or desirous of concealment. The fossil known to geologists by the name of Belemnite is the internal skeleton of an animal very much like the cuttle-fish, but provided, not only with a solid framework for the attachment of muscles, but also with an apparatus like that possessed by the Nautilus and the Ammonite. The animal of the Belemnite was enclosed within a muscular shape, which formed a kind of closed bag terminating above with the head. "From around this eight arms proceeded, whose length in the species examined seems to be about one-fourth part of the entire length of the animal; and each arm was provided with from fifteen to twenty pairs of hooks, resembling those now seen only in the most powerful and the fiercest of the whole tribe of Cephalopoda, and used to pierce the flesh of fishes and other animals, in order to secure firm hold when the Belemnite was about to seize its prey. The head was provided with very large eyes; the jaws were probably horny; and, besides the eight arms, there seems to have been one pair of long tentacles. Far down below the head, and within the cavity of the shell, there was placed an oval sac containing a black fluid, communicating by a tube with the aperture. This fluid exactly resembles the ink of the common cuttle-fish; and there can be no doubt that it was used by the animal in the same way, and for the same purpose, namely, to darken the water when its possessor, becoming alarmed, desired to escape. The ink itself in a solid state, the bag which contained it, and the tube or pen by which it was shot out into the water, are all preserved in some of the specimens of this fossil. The mantle of the Belemnite, passing over the guard or shell, seems to have accommodated itself to the shape of the shell, and terminated in a blunt point. Two fins, however, of a rounded form, and of considerable size, extended on each side near the middle of the animal. From this position of the fins, from the shape of the shell, and from its general structure, it has been concluded that the animal commonly remained in a vertical position, rising and sinking with great facility, and possessing very unusual powers of locomotion and destruction."