With sparkling mineral, or should crystal cube
Lurk in its cells and thinks himself enriched.
Wealthier, and doubtless wiser, than before!"
There was nothing in the distant aspect of the boulder to attract attention. It was just such a mass as dozens of others all round. Nor, on closer inspection, might anything peculiar have been observed. It had an irregularly oblong form, about two or three feet long, and half as high. Ferns and herbage were grouped around it, the wood-sorrel clustered up its sides, and little patches of moss and lichen nestled in its crevices. And yet, withal, there was something about it that, ere long, riveted my attention. I examined it minutely from one end to the other, and from top to bottom. The more I looked the more did I see to interest me; and when, after a little labour, some portions of its upper surface were detached, my curiosity was abundantly gratified. That grey lichened stone, half hid among foliage, and unheeded by any human being, afforded me material for a pleasant forenoon's thought. Will my reader accept an expanded narrative of my reverie?
I can almost anticipate a smile. "What can there be remarkable in such a grey stone, hidden in a wood, and of which nobody knows anything? It never formed part of any ancient building; it marks the site of no event in the olden time; it is linked with nothing in the history of our country. What of interest, then, can it have for us?" Nay, I reply, you are therein mistaken. It is, assuredly, linked with the history of our country—it does mark the passing of many a historical event long ere human history began; and, though no tool ever came upon it, it did once form part of a building that rose under the finger of the Almighty during the long ages of a bygone eternity. To change the figure, this boulder seemed like a curious volume, regularly paged, with a few extracts from older works. Bacon tells us that "some books are to be tasted, others to be swallowed, and some few to be chewed and digested." Of the last honour I think the boulder fully worthy, and if the reader will accompany me, I shall endeavour to show him how the process was attempted by me.
The rock consisted of a hard grey sandstone finely laminated above, and getting pebbly and conglomeritic below. The included pebbles were well worn, and belonged to various kinds of rock. The upper part of the block was all rounded, smoothed, and deeply grooved, and, when split open, displayed numerous stems and leaflets of plants converted into a black coaly substance. These plants were easily recognisable as well-known organisms of the carboniferous strata, and it became accordingly evident that the boulder was a block of carboniferous sandstone. The pebbles below, however, must have been derived from more ancient rocks, and they were thus seen to represent some older geological formation. In this grey rock, therefore, there could at once be detected well-marked traces of at least two widely-separated ages. The evidence for each was indubitable, and the chronology of the whole mass could not be mistaken. The surface striation bore undoubted evidence of the glacial period, the embedded plants as plainly indicated the far more ancient era of the coal-measures, while the pebbles of the base pointed, though dimly, to some still more primeval age. I had here, as it were, a quaint, old, black-letter volume of the middle ages, giving an account of events that were taking place at the time it was written, and containing on its earlier pages numerous quotations from authors of antiquity. The scratched surface, to complete the simile, may be compared to this old work done up in a modern binding. Let us, then, first of all, look for a little at the exterior of the volume, and inquire into the origin of that strangely-striated surface, and of the clay in which the boulder rested.
CHAPTER II.
Exterior of the boulder—Travelled stones a difficult problem—Once referred to the Deluge—Other theories—Novelty of the true solution—Icebergs formed in three ways—Progress and scenery of an iceberg—Its effects—Size of icebergs—Boulder-clay had a glacial origin—This explanation confirmed by fossil shells—Laws of the distribution of life—Deductions.
Has the reader, when wandering up the course of a stream, rod in hand perhaps, ever paused at some huge rounded block of gneiss or granite damming up the channel, and puzzled himself for a moment to conjecture how it could get there? Or when rolling along in a railway carriage, through some deep cutting of sand, clay, and gravel, did the question ever obtrude itself how such masses of water-worn material came into existence? Did he ever wonder at the odd position of some huge grey boulder, far away among the hills, arrested as it were on the steep slope of a deep glen, or perched on the edge of a precipitous cliff, as though a push with the hand would hurl it down into the ravine below? Or did he ever watch the operations of the quarryman, and mark, as each spadeful of soil was removed, how the surface of the rock below was all smoothed, and striated, and grooved?
These questions, seemingly simple enough, involve what was wont to be one of the greatest problems of geology, and not many years have elapsed since it was solved. The whole surface of the country was observed to be thickly covered with a series of clays, gravels, and sands, often abounding in rounded masses of rock of all sizes up to several yards in diameter. These deposits were seen to cover all the harder rocks, and to occur in a very irregular manner, sometimes heaped up into great mounds, and sometimes entirely wanting. They were evidently the results of no agency visible now, either on the land or around our coasts. They had an appearance rather of tumultuous and violent action, and so it was wisely concluded that they must be traces of the great deluge. The decision had at least this much in its favour, it was thoroughly orthodox, and accordingly received marked approbation, more especially from those who wished well to the young science of geology, but were not altogether sure of its tendencies. But, alas! this promising symptom very soon vanished. As observers multiplied, and investigations were carried on in different countries, the truth came out that these clays and gravels were peculiarly a northern formation; that they did not appear to exist in the south of France, Italy, Asia Minor, Syria, and the contiguous countries. If, then, they originated from the rushing of the diluvian waters, these southern lands must have escaped the catastrophe, and the site of the plains of Eden would have to be sought somewhere between the Alps and the North Pole. This, of course, shocked all previous ideas of topography; it was accordingly agreed, at least among more thoughtful men, that with these clays and sands the deluge could have had nothing to do.