In the course of the day I picked up a nodular mass of blue limestone, and laid it open by a stroke of the hammer. Wonderful to relate, it contained inside a beautifully finished piece of sculpture, one of the volutes, apparently, of an Ionic capital. Was there another such curiosity in the whole world? I broke open a few other nodules of similar appearance, and found that there might be. In one of these there were what seemed to be scales of fishes and the impressions of a few minute bivalves, prettily striated; in the centre of another there was actually a piece of decayed wood.
Of all nature's riddles these seemed to me to be at once the most interesting and the most difficult to expound. I treasured them carefully up, and was told by one of the workmen to whom I showed them that there was a part of the shore, about two miles further to the west, where curiously shaped stones, somewhat like the heads of boarding-pikes, were occasionally picked up, and that in his father's day the country people called them thunderbolts. Our first half-holiday I employed in visiting the place where the thunderbolts had fallen so thickly, and found it a richer scene of wonder than I could have fancied even in my dreams.
My first year of labour came to a close, and I found that the amount of my happiness had not been less than in the last of my boyhood. My knowledge had increased in more than the ratio of former seasons; and as I had acquired the skill of at least the common mechanic, I had fitted myself for independence.
My curiosity, once fully awakened, remained awake, and my opportunities of gratifying it have been tolerably ample. I have been an explorer of caves and ravines, a loiterer along sea-shores, a climber among rocks, a labourer in quarries. My profession was a wandering one. I remember passing direct, on one occasion, from the wild western coast of Ross-shire, where the Old Red Sandstone leans at a high angle against the prevailing quartz of the district, to where, on the southern skirts of Midlothian, the Mountain Limestone rises amid the coal. I have resided one season on a raised beach of the Moray Firth. I have spent the season immediately following amid the ancient granite and contorted schists of the central Highlands. In the north I have laid open by thousands the shells and lignites of the oolite; in the south I have disinterred from their matrices of stone or of shale the huge reds and tree ferns of the carboniferous period.
I advise the stone-mason to acquaint himself with geology. Much of his time must be spent amid the rocks and quarries of widely separated localities, and so, in the course of a few years he may pass over the whole geological scale, and this, too, with opportunities of observation at every stage which can be shared with him by only the gentleman of fortune who devotes his whole time to study. Nay, in some respects, his advantages are superior to those of the amateur, for the man whose employments have to be carried on in the same formation for months, perhaps years, enjoys better opportunities of arriving at just conclusions. There are formations which yield their organisms slowly to the discoverer, and the proofs which establish their place in the geological scale more tardily still. I was acquainted with the Old Red Sandstone of Ross and Cromarty for nearly ten years ere I ascertained that it is richly fossiliferous; I was acquainted with it for nearly ten years more ere I could assign its fossils to their exact place in the scale. Nature is vast and knowledge limited, and no individual need despair of adding to the general fund.
II.—Bridging Life's Gaps
"The Old Red Sandstone," says a Scottish geologist in a digest of some recent geological discoveries, "has hitherto been considered as remarkably barren of fossils." Only a few years have gone by since men of no low standing in the science disputed the very existence of this formation—or system, rather, for it contains at least three distinct formations. There are some of our British geologists who still regard it as a sort of debatable tract, entitled to no independent status, a sort of common which should be divided.
It will be found, however, that this hitherto neglected system yields in importance to none of the others, whether we take into account its amazing depth, the great extent to which it is developed both at home and abroad, the interesting links which it furnishes in the geological scale, or the vast period of time which it represents. There are localities in which the depth of the Old Red Sandstone fully equals the elevation of Mount Etna over the level of the sea, and in which it contains three distinct groups of organic remains, the one rising in beautiful progression over the other.
My first statement regarding the system must be much the reverse of the one just quoted, for the fossils are remarkably numerous and in a state of high preservation. I have a hundred solid proofs by which to establish the truth of the assertion within less than a yard of me. Half my closet walls are covered with the peculiar fossils of the Lower Old Red Sandstone; and certainly a stranger assemblage of forms has rarely been grouped together—creatures whose very type is lost, fantastic and uncouth, which puzzle the naturalist to assign them even to their class; boat-like animals, furnished with oars and a rudder; fish, plated over, like the tortoise, above and below, with a strong armour of bone, and furnished with but one solitary rudder-like fin; other fish with the membranes of their fins thickly covered with scales; creatures bristling over with thorns; others glistening in an enamelled coat, as if beautifully japanned; the tail in every instance among the less equivocal shapes formed not equally, as in existing fish, on each side the central vertebral column, but chiefly on the lower side—the column sending out its diminished vertebræ to the extreme termination of the fin. All the forms testify of a remote antiquity. The figures on a Chinese vase or an Egyptian obelisk are scarce more unlike what now exists in nature than are the fossils of the Lower Old Red Sandstone.
Lamarck, on the strength of a few striking facts which prove that to a certain extent the instincts of species may be improved and heightened, has concluded that there is a natural progress from the inferior orders of being towards the superior, and that the offspring of creatures low in the scale may belong to a different and nobler species a few thousand years hence. Never was there a fancy so wild and extravagant. The principle of adaptation still leaves the vegetable a vegetable, and the dog a dog. It is true that it is a law of nature that the chain of being is in some degree a continuous chain, and the various classes of existence shade into each other. All the animal families have their connecting links. Geology abounds with creatures of the intermediate class.