We now take our leave of the Palæozoic period, and enter upon the investigation of other and more recent geological epochs in the history of the crust of our planet. This division is known by the names Secondary or Mesozoic,^[64] and is inclusive of the New Red Sandstone, Oolitic, Wealden, and Cretaceous groups. If, in our previous survey, we have had our minds filled with wonder as we looked at the disinterred relics of past creations, and have gazed at these fossil forms of ancient life with almost a loving interest in their still remaining beauty; so, as we now study higher types of life, and behold how “other wonders rise, and seize the soul the prisoner of amaze,” we shall find reason upon reason for the penetration of our minds with the profoundest adoration of Deity. No man turning up a tumulus, and there finding coins, weapons, beads, vases, or other such historical relics, would venture to say such things were created there; on the contrary, he would acknowledge that they were Roman, and that he had come to that conclusion by perceiving their resemblance to other and similar ancient Roman relics, discovered where there could be no doubt of their origin and history. Or if a traveller were to visit the cities of Herculaneum and Pompeii, and there find buried beneath the overwhelming torrent of once burning lava, all possible kinds of human memorials, not only in human works, but also in the skeleton remains of human beings, would he not come to the conclusion that these were indubitable evidences of those cities having once been inhabited by man, and that these skeletons were once covered with warm flesh, and that they had lived, and moved, and had their being, even as we do now, amidst the activities and enjoyments of actual life? We apply this to geology. There are persons who never judge by evidence, (though what else have we to judge by?) but rashly jump to conclusions about geological facts, that have not a particle of common sense to sustain them. They never think that every rounded pebble they meet with has been so rounded by the action of water; they imagine sand to have been created as sand, instead of taking the geologist’s proof, that all sand has been produced by the action of moving water on solid rock. They believe that fossils were created, and that God put encrinital remains, and dead ammonites, and bones of saurians, and teeth and bones of great mammals, in the earth, just as we find them in the cliffs and caves of this and every country; and they imagine that thus to account for the wonders of creation redounds to the glory of that God whom thus they ignorantly worship. Even our great publishing society in Paternoster Row,^[65] that has published about everything in natural history but geology, has acknowledged to me that it declines to undertake a work on this science, because of the theological difficulties connected with the subject. Why, what is this but the very way to breed infidelity? The man who studies nature and who studies his Bible, is not ashamed to say he believes them both; though two books, they are both given by inspiration of God. Man may be a liar, but neither nature nor the Bible can lie; and while one tells us the history of man, the other reveals to us the history of the creation, and succession of those beings which preceded the advent of man.

We now come to the New Red Sandstone, which must occupy our attention both on account of the unique fossil remains found in it, and also on account of its economic use and value in commerce. Few formations, small as it is, possess so many points of interest to the beginner as the new red sandstone; for, lying just above the carboniferous, and between it and the oolitic group, we find in it certain curiosities of very olden time, that are full of marvellous power to fill us with amaze. Every one remembers Robinson Crusoe’s surprise at finding “the print of a man’s naked foot on the shore, which was very plain to be seen in the sand,” and how he “stood like one thunder-struck, or as if he had seen an apparition;” and then how he “went again to see if it might not be his fancy, but there was no room for that, for there was exactly the very print of a foot, toes, heel, and every part of a foot;” and then how, after “innumerable fluttering thoughts, and out of himself,” he went home terrified to his fortification.

Equally surprising are the discoveries made in the old red sandstone. Large slabs of this rock have been discovered in England, in Scotland, and in the United States, on which are left, as Robinson left the impression of his foot, the undisturbed footmarks of pre-Adamite animals; the ebb and flow of the tide of those distant ages; the ripple-mark showing the direction of the wind; and casts of the rainprints made by showers, long long ages ere man had taken possession of the “deep places of the earth.” “Romantic nonsense!” says a grave friend; “let us go to something practical, instead of losing ourselves in such idle speculations.” Now, you are just the person whose ear we want to catch; and to you we say, just listen to the evidence of these assertions. “The casts of rainprints below project from the under side of two layers; the one a sandy shale, and the other a sandstone presenting a warty or a blistered surface, and affording evidence of cracks formed by the shrinkage of subjacent clay on which rain had fallen. The great humidity of the climate of the coal period had been previously inferred from the nature of its vegetation, and the continuity of its forests for hundreds of miles; but it is satisfactory to have at length obtained such positive proofs of showers of rain, the drops of which resembled in their average size those which now fall from the clouds. From such data we may presume that the atmosphere of the carboniferous period corresponded in density with that now investing the globe and that different currents of air varied then as now in temperature, so as to give rise, by their mixture, to the condensation of aqueous vapour.”^[66]

Again, let us hear the words of Professor Ansted. “It may appear at first sight that nothing can be more fleeting, or less likely to be handed down to future ages, among the fossils of a bed of sandstone, than the casts of the impressions of the footsteps of an animal, which by chance may have walked over that bed when it existed in the condition of loose sand forming a seashore. A little consideration, however, will show that it is in fact a very possible occurrence, as, if the wet sand should be immediately covered up with a thin coating of marl, and another layer of sand be superimposed, such an impression will be permanently preserved. In after ages, also, when the soft sands have become sandstones, and are elevated above their former level, the stones split asunder wherever a layer of different material occurs; and thus it happens that the casts of the footsteps may be preserved and exhibited, although all other traces of the former existence of the animal have been lost.”^[67]

If we go to the British Museum, on the north wall of room No. 1. we shall find slabs of sandstone containing footprints of animals, apparently bipeds and quadrupeds, of which we find the following notice in the catalogue of the Museum; and when this description is compared with the three drawings that follow, we make no doubt of carrying the conviction of the reader along with our own, as to the origin of these extraordinary ichnites,^[68] as such petrified prints are termed:—“The slabs of sandstone on the north wall of this room, with the supposed tracks of an animal called Cheirotherium, are that on the left from the quarries of Hildburghausen in Saxony, and that in the centre from those of Horton Hill, near Liverpool, (the latter presented by J. Tomkinson, Esq.) On the right hand are placed slabs from the same new red sandstone formation, with equally enigmatical imprests of various dimensions, called Ornithichnites,^[69] being very like footmarks of birds; they occur in the sandstone beds near Greenfield, Massachusetts, at a cataract in the Connecticut River known by the name of Turner’s Falls.”

The lines in this drawing are merely to indicate the direction, the line of progress, of these bipeds, and the reader by following the lines will find the illustration all the more interesting.

But the most remarkable footprints preserved on slabs of sandstone are those of a quadruped, whose hinder feet were much larger than his fore feet. Some of our marsupial^[70] quadrupeds, such as the opossum and kangaroo, and many species of batrachian^[71] reptiles, are distinguished by the same peculiarity. Below is a copy of this slab, which is in the window recess of the same room of the British Museum.

The animal that left these impressions on the soft sandy shore, that are now converted into hard stone, was originally named the Cheirotherium,^[72] and, indeed, this name is still retained by many writers, the hand-like footprints being quite a sufficient reason for so appropriate a name; but latterly the teeth of a fossil animal, supposed to be the same as the Cheirotherium, having been examined, and disclosing a peculiarly labyrinthine character, the animal has been called Labyrinthodon.^[73] Professor Owen, the great comparative anatomist of geology, has fairly established the real character of this animal. He says it is a huge frog, a gigantic batrachian, with hinder feet at least twelve inches in length, combining a crocodilian with a frog-like structure; and although the actual shape and proportions of such an animal must remain greatly an enigma, it is one of the wondrous marvels of geology to pause over these extinct huge creatures, and mark in them the exhaustless resources of creative power.

In Professor Ansted’s remarkable prose poem on geology, called, “The Ancient World,” we have the following picture of the new red sandstone period, which we quote for its vivid but faithful colouring:—“We may imagine a wide, low, sandy track by the sea-side; the hills and cliffs of limestone, which still rise boldly on the shores of the Avon, and in Derbyshire and Yorkshire, having then been recently elevated, and forming a fringe to the coast line. In some places, where footprints are found in successive beds and at different levels, local elevation was probably going on, and the line of coast was occasionally shifting. The sandy fiats thus laid bare, and not reached by the ordinary level of high water, were of course traversed by the ancient animals of that period; but only a few faint records of them have been handed down for our observation. Amongst these, however, we are able to enumerate turtles and tortoises, a little lizard having a bird-like beak, and probably a bird’s foot,—birds themselves, some larger than an ostrich, others as small as our smaller waders. In some parts of the world there were also large reptiles with powerful tusks, not surpassed in the amount of their departure from the ordinary structure of reptiles by any known aberrant forms of that strange and varied tribe.

“Amongst the most striking of these objects, at least on our own shores, would be the numerous and gigantic Labyrinthodons. We may imagine one of these animals, as large as a rhinoceros, pacing leisurely over the sands, leaving deep imprints of its heavy, elephantine hind foot, strangely contrasting with the diminutive step of its short fore extremities. Another, a small variety, provided like the kangaroo, not only with powerful hind legs, but also with a strong tail,^[74] also leaves its impress on the sand, although itself, perhaps, soon fell a victim to the voracity of its larger congener. These and others of their kind, passing over the sands, and marking there the form of their expanded feet, marched onwards in their course, fulfilled their part in nature, and then disappeared for ever from the earth, leaving, in some cases, no fragment of bone, and no other indication of their shape and size than this obscure intimation of their existence.

“It is strange that in a thin bed of fine clay, occurring between two masses of sandstone, we should thus have convincing evidence preserved concerning some of the earth’s inhabitants at this early period. The ripple mark, the worm track, the scratching of the small crab on the sand, and even the impression of rain drops, so distinct as to indicate the direction of the wind at the time of the shower,—these and the footprints of the bird and the reptile are all stereotyped, and offer an evidence which no argument can gainsay, no prejudice resist, concerning the natural history of a very ancient period of the earth’s history. But the waves that made that ripple mark have long since ceased to wash those shores; for ages has the surface then exposed been concealed under great thicknesses of strata; the worm and the crab have left no solid fragment to speak to their form or structure; the bird has left no bone that has yet been discovered; and the fragments of the reptile are small, imperfect, and extremely rare. Still, enough is known to determine the fact, and that fact is the more interesting and valuable from the very circumstances under which it is presented.”^[75]

But reminding ourselves of one part of the title of our book, which professes not only to describe the crust of the earth, but also to point out its uses, we must add a few words on the economic value of this small but interesting formation. In this same new red sandstone are found the salt mines of Cheshire, and the brine pits of Worcestershire, which supply all the rock and table salt consumed in England, besides vast quantities for exportation. The rock salt of Cheshire was first discovered near Northwich, while searching for coal; but the largest mine, called the Wilton Mine, is at Nantwich, and still yields about 60,000 tons of salt annually. The salt is generally found from twenty-eight to forty-eight yards beneath the surface, in thick strata varying from fifteen to thirty-five yards in thickness. Besides these beds of salt, there are brine springs from twenty to forty yards in depth. Our common table salt is almost exclusively derived from these springs, which is produced by evaporating the water, and allowing the salt to settle at the bottom of the pans, where, after being washed, it is placed in moulds like the China clay, and comes to our grocers’ shops in the blocks we frequently see. “So far as observation has yet gone, the English supply is practically inexhaustible; no limit is known to the extent of the beds or the springs; and it ought to be regarded as one of the blessings which we owe to the mineral wealth of our country, that the beautiful table salt of England may be obtained at such an extremely low price as that now charged for it.”^[76]

To this formation, with its fossil footprints, we owe doubtless the fine fancy of Longfellow, in one of his sweet minor poems; and we shall bring this chapter to a close by quoting the last three verses of this lyric. If we can fulfil such a mission, we had better be frail and erring men than huge Labyrinthodons:—