The Irish Penny Journal, Vol. 1 No. 38, March 20, 1841

by Various

KNOWLEDGE AND IGNORANCE.

Second Article.
BOULDERS—CONTINUED.

If the dreary waste of the sandy desert, when the hot and suffocating blast sweeps over its parched surface, appears to the affrighted traveller invested with all the characters of sublimity, not less impressed with awe is the wanderer of polar regions, when, gazing on the heart-chilling magnificence of the interminable ice which surrounds him, he hears the sigh of the coming snow-storm, fraught with danger or with death. But at a time when repeated voyages and spirit-stirring narratives have rendered familiar to every one the beauties and the dangers of ice in every conceivable form of floe, of field, or of berg, and have excited sympathy for the sufferings or admiration of the daring of those who, to advance the cause of science, or to pursue for commercial purposes the mighty whale, have ventured within the precincts of that icy kingdom, it is not necessary to describe the solitary grandeur of a scene in which ice spreads like a sea beneath the feet, and rises as a mountain above the head. Not even, then, by the side of a cheerful fire, in these more temperate regions, shall we unnecessarily indulge in shudderings at the thought of distant powers of congelation, or enter further into the subject of polar picturesqueness. It is as a geological agent that we have now to contemplate ice in the various forms of fields and bergs, or of glaciers; its efficiency as a moving power being first considered. Scoresby justly denominates ice-fields “one of the wonders of the deep. They are often,” he says, “met with of the diameter of twenty or thirty miles; and when in a state of such close combination that no interstice can be seen, they sometimes extend to a length of fifty, or nearly a hundred miles.” The average thickness of these fields is from ten to fifteen feet, and their surface is varied by hummocks, which rise to a height of from forty to fifty feet. The weight of a piece of field ice, one mile square and thirteen feet thick, is, according to Scoresby’s estimate, 11,314,284 tons; and from the difference of specific gravity between ice and sea-water, this floating mass is sufficiently buoyant to support a weight of stones or other heavy bodies equal to 1,257,142, or in round numbers one million tons.

Grand, however, as such floating fields of ice are, they are exceeded in magnificence by bergs. One of these, Scoresby relates, was one mile in circumference, fifteen hundred feet square, and a hundred feet above the level of the sea; so that, allowing for the inequalities of its surface, he considered its depth in the water seven hundred feet, its total thickness eight hundred feet, and its weight about forty-five millions of tons—an enormous mass, capable of transporting at least five millions of tons of extraneous weight. In number, too, they are as remarkable as in magnitude: above five hundred were counted by Scoresby from the mast-head at one time, of which scarcely one was less than the hull of a ship, about a hundred as high as the ship’s mast, and some twice that height, or two hundred feet above the surface of the sea; hence in total thickness about sixteen hundred feet. These, then, it must be admitted, are mighty engines fitted for the transport of rocks of colossal magnitude. But in the reasonings of sound philosophy, the apparent fitness of an object to perform some particular function cannot be deemed sufficient to establish the reality of its action: further proof is necessary, either derived from analogy or from positive facts. In respect to ice-fields, the easiest of observation, it is remarkable that neither of the Captains Scoresby speaks of having noticed extraneous matter upon them, unless the expression “heaps of rubbish,” in a passage of the voyage of Scoresby senior, means rubbish of stones as well as rubbish of ice. Examples will indeed be quoted from other writers, but the comparative scarcity of transported matter on the upper surface of the fields of ice, seems a natural consequence of their mode and place of formation. Formed in bays or gulfs, some portions of them are broken off by the violence of the waves at a distance from the shore, and never therefore come in contact with rocks or stones; whilst others, grounding in shallow water, encase many in the substance of their lower surface, although none are seen on the upper.

The conditions, indeed, which are necessary to ensure a load for the carrying ice, such as proximity to the rocks the detached fragments of which are to rest on its surface, are more peculiarly present in ice formed under or brought into contact with precipitous rocky banks, and in that formed in deep narrow gulfs—in short, in ice constituted after the manner of glaciers. A large portion, therefore, of field ice must necessarily float about unencumbered with rubbish or fragments of rocks. Boethlingk, in treating on the diluvial and alluvial formations of South Finland, incidentally touches upon this subject. “The dispersion,” he observes, “of these blocks, is very probably in accordance with a phenomenon which may be observed on many seas and rivers, and which depends on the presence of blocks of stone near the shore. Through what force and in what manner the deposition of large blocks on the surface of all those formations which are at the water’s brink even now happens, can be observed every spring, by any one who, at the breaking up of the ice, repairs to those parts of the coast where the shore bears testimony, by the numerous blocks heaped up one upon the other, of their forcible deposition. Near Kiwinjemei, on the Wwoxen, there is, as it were, a wall nine feet high, stretching along the flat shore, composed of blocks of stone which have been gradually raised by the masses of ice. In several places such stones, three feet in diameter, were lying on flakes of ice, which, pressing onwards to the shore, had been shoved one over the other to the height of six or eight feet; so that no one could doubt the fact that the ice-flakes had been the carriers of the stones; and also, where the steepness of the ground permits the near approach of ice-shoals to the shore, that the blocks would be heaped up one over the other into a terrace or wall; whilst, on the contrary, on shallow coasts they would be scattered in the water, at a distance from the shore. The deposition of blocks depends therefore on the shore being accessible to ice-shoals driven in by winds or currents. Small blocks, also, are often cemented together by ice when the water over shallows, the bottoms of which are covered with loose stones, freezes; and when the water rises in the spring, or in consequence of storms setting in from the sea, the ice also rises, and with it the encased stones; and being driven out to sea, the stones, by the melting of the icy cement, are dropped in various places. In this way it is very probable that the boulders which lie scattered over the surface of the countries south of the Baltic were transported from Scandinavia and Finland on ice-shoals, at a time when the East Sea yet spread over those regions. Banks also are thrown up along the shore by the ice; they are never composed of large stones, but on flat sandy shores principally of sand.

Where the water-level was constant for a considerable time, during which banks were formed, they show by their height above the present flow of the water how much the condition of the latter has been changed. When two such banks lie one behind the other, at the same level, or successively like terraces, we are justified in concluding that the level of the water has changed and the land been increased, or that the one has sunk and the other in consequence advanced upon it. In confined basins this sinking may have been the consequence of the outlet widening by wear, and in open seas by the upheaving of the land. On all the large lakes of Finland are seen banks and terraces, as well as single blocks of stone, on the slopes. The terraces often lie one above the other, which indicates sudden depressions of the water’s surface at different periods, each bank or terrace marking the water-line of a particular period, in which were deposited in strata many kinds of detritus mixed up with vegetable substances.” These remarks of Boethlingk, originally recorded in the “Bulletin of the Academy of Sciences of St Petersburg,” are here cited from the “Neues Jahrbuch von Leonhard und Bronn.” They are valuable, as results of personal observation, and have doubtless already given a tolerable inkling of the reasons upon which this species of explanation of the phenomenon of boulders has been founded. Captain Bayfield, of the Royal Navy, the able surveyor of the Canadian lakes and of the river St Lawrence, records similar facts observed by him in that river. The St Lawrence is in winter low, and the ice on the shallows along both banks of the river is frozen into one connected mass by a temperature which often sinks to thirty degrees below zero, or sixty-two degrees below the freezing point. When the thaw sets in, these masses are raised up and floated away, and with them an extraordinary quantity of blocks and stones which had been encased by the frost in their substance. In like manner, anchors which for the security of the ship in winter had been fixed near the shore, were obliged to be cut out of the ice, or they would have been carried away. Half a ton weight of one of the strongest chain cables was torn off and carried many yards away, when means were taken to cut it out. Captain Bayfield also mentions the fact that he had often seen at sea icebergs laden with stones, in the Straits of Belleisle the captain examined one amongst many which must have come from Baffin’s Bay; it was thickly covered over with blocks, gravel, and stones. M. Reinecke, an officer of the Russian navy employed on a survey of the coast of Finland, relates two pleasing though minor incidents of a similar kind. The fishermen of Sweaborg pointed out to his officers that the sea-bottom of their coast was subject to frequent change, partly from the action of the waves in violent storms, but more particularly from the force of traction exercised by enormous bodies of ice which are set adrift at the breaking up of the frost, and being arrested in their progress by some of the numerous headlands of the coast, or by the shoals which there encumber the sea, are heaped up one upon the other into colossal masses, which, liberated by some new shock, are again violently urged forward, and drag along with them the sand of the bottom, and even large fragments of the rocks. At the village of Kittelholm, near Sweaborg, the inhabitants directed the officers’ special attention to two such erratic blocks of stone, which at a very recent period had changed their place: resting on a rock of the coast called Witthella, and at a height of three sagènes (about 21 feet) above the level of the sea, there now appears a block of granite, called by the sailors “sea calf,” from its resemblance to a seal basking in the sun. This block was first seen in its present position in 1815. It had been encased in a mass of ice, which, raised up by the waves in a storm, had rested on the level top of the rock, and there melted as it thawed: the boulder, brought probably from a distant region, being left where it now stands. The other erratic block or boulder of Kittelholm had been observed by the inhabitants in the winter of 1806 to shift its place, being dragged on by the ice for a distance of about one-third of a mile. But all these were carriers of small note and name when compared to those of vast bulk and power described by Scoresby. “Many,” says he, “of the icebergs contained strata of earth and stones, and some were loaded with beds of rock of great thickness, and weighing by calculation from 50,000 to 100,000 tons.” When, therefore, we see such operations going forward in our own time—the iceberg loaded with its freight of gravel and of rocks, moving slowly from the frozen north to the south, where, melted by the increasing heat, it is destined to discharge its cargo indiscriminately on mud, on gravel, or on rock, in the plain or on the hill, in the valley or on the mountain top (for all these forms of matter and of feature may be reasonably assumed to diversify the bottom of the present ocean, as it did that of a former one, now the surface of our dry land)—may we not conclude with Lyell or with Wissman, with Murchison or with Darwin, that were that bottom exposed dry to our view, it would in like manner exhibit its phenomena of gravel and of boulders?

Nor would those appearances be confined to the northern regions; the reign of frost and snow has extended over a wider space in the antarctic than it has in the arctic circle. Mr Murchison quotes from a letter of Captain Harcourt, R. N., who in returning from South America met with a vast number of ice-floes in the Pacific, in latitude 50 degrees. Some of them were not less than two miles square, and 250 to 300 feet above the water, and consequently about 2000 feet thick. It is remarkable that this phenomenon occurred from 85 degrees west longitude, at a considerable distance from any land, to the meridian of Cape Pillar, while the immediate coasts of Chili and Cape Horn offered no trace of them. The winter was comparatively mild, which might indeed account for the liberation of such large masses of ice from the South Pole, and their being wafted into seas usually quite free from them. The number and size of these ice-floes were so astonishing, that Captain Harcourt, during the long winter moonless nights of eighteen hours, had great difficulty in steering through them without shipwreck; their course seemed to be from south-east to north-west, and they were met with through five degrees of latitude (50 to 55 degrees), which would be the exact position of England if transferred to the other hemisphere. May we not then shudder at the thought of that dreary future, in which, by some physical changes of the earth’s surface, according to the theory of Mr Lyell, the conditions of the earth’s superficial temperature may be reversed, and bring down upon the coasts of our ill-fated island those frost-bearing monsters to bite up every living thing by one common congelation; for we may well suppose, that long ere that dismal period our cold-dispelling fuel, turf, coal, and all, will have been utterly consumed. But let us comfort ourselves with this selfish reflection—it will not be in our day.

Numerous as the icebergs of the antarctic regions are, they have as yet afforded few examples of transported materials. One, however, of very considerable interest, is thus recorded in a Journal of Discoveries in the Antarctic Ocean in 1839, by Mr John Balleny, communicated to the Geographical Society by Mr Enderby, the ship-owner. “March 13. Light variable winds from the eastward; surrounded by icebergs. In latitude 61 degrees, longitude 103 degrees 40 minutes, passed within a quarter of a mile of an iceberg about 300 feet high, with a block of rock attached to it.” The rock is described as about 12 feet in height and about one-third up the berg. The nearest certainly known land (Enderby’s Land) was distant from the spot 1400 miles; Sabrina Land, if such exists, was distant 450 miles; and it is very improbable that any land will be discovered within 100 miles. Mr Darwin, in an interesting note on this Journal, mentions a preceding case of an iceberg with a considerable block lying on it, seen east of South Shetland by Mr Sorrell, when in a sealing vessel; and though another voyager, Captain Briscoe, during several cruises in the antarctic seas, had never once seen a piece of rock in the ice, he remarks, that if but one iceberg in a thousand or in ten thousand transports its fragment, the bottom of the antarctic sea and the shores of its islands must already be scattered with masses of foreign rock, the counterpart of the erratic boulders of the northern hemisphere.

Such, then, are the facts on which modern geologists, and more especially Mr Lyell, have founded the theory of ice-transported boulders, appealing to the experience of that which is now occurring in existing seas as evidence of that which did occur in seas not now existing—seas which once covered or at least rose to the level of places which exhibit these relics of their presence. Presuming, then, for an instant, that the fact is conceded, that at some ancient epoch the low lands of a large portion of the northern and southern hemispheres were under water, whilst the higher hills and mountains were covered with snow, and their gorges and valleys filled with glaciers, which on descending to the ocean carried with them fragments of rocks, and became as icebergs their carriers to distant regions, do we not obtain an explanation of the phenomena of boulders more simple and rational than any of those previously advanced? For example, Kirwan in his Essays tells us that the Bay of Galway must have been occupied by a granitic mountain, which in a great catastrophe was shattered and swallowed up, because he found a mass of granite called “the Gregory” on one of the isles of Arran, 100 feet above the sea, and 8 or 10 miles from the nearest granitic locality, the islands themselves being limestone. But such a mass, though 20 feet long, 10 high, and 11 broad, if floated across on an iceberg, could have been deposited at its destined place by machinery more simple than such a catastrophe. In like manner, how easily the granitic blocks of Scandinavia could by similar means have been transported across the Baltic!—and at the same time many of the phenomena of drift (a name now given by many geologists to what was formerly called diluvian) might be explained, as shown by Mr Lyell in his account of the Norfolk drift, by the action of floating fields of ice carrying with them sand and gravel, or grating and heaping up the sand and gravel of shoals on which they were beginning to ground, as shown in the examples cited. The long lines of drift and boulders extending from north to south in northern Europe were indeed in all probability the result of the joint operation of the marine current which moved onwards the floating ice, and of the ice itself. In these lines or trainées, two sets have been discovered—one crossing the other at a very acute angle, a circumstance which may possibly be explained by supposing two currents simultaneously running from the north being inflected by local peculiarities into slightly differing directions, and then, on meeting, proceeding in a direction the resultant of the two; the direction of the resultant varying at different epochs according as one or the other current, from varying local causes, possessed the greater or less velocity; if so, the natural result of such meeting currents would be to deposit along their resulting direction lines of drift, to form in this manner shoals on which the floating ice would occasionally ground, and by its load of gravel and boulders assist the work of detritic accumulation.

In as far, then, as the phenomenon of boulders is exhibited in the low lands of Europe (leaving other countries out of the question), it seems quite in conformity with the operations of causes such as have been here explained. But it may next be asked, How does the ice-transporting theory explain the boulders of the Alps? Had the waters been sufficiently elevated to convey icebergs over the Jura chain, the Scandinavian mountains would have been deeply submerged, and no longer, therefore, a source either of ice or of boulders. This is unquestionably a difficulty, unless it be assumed either that some great change of relative altitude has taken place by the uplifting of the Alps since the deposition of its boulders, or that the Alpine boulders have not been conveyed by marine agencies. Lyell supposed it possible that falling “hill-sides” might have dammed up the rallies of Switzerland, and have formed lakes, on which the icebergs from its uplifted glaciers might have floated across to the Jura, and have been carried down to the low country at the base of the Alps, by the sudden bursting of the barrier, and the flood following it; and Wissmann (who strangely enough ranks Lyell, manifestly his precursor in this idea, amongst the advocates of the theory of torrents) in like manner assumes the existence of a large sea extending over the low portion of Switzerland, the country now bordering on the Lake of Constance, and the greater part of Bavaria, on the waters of which the ice of falling glaciers with its cargo of boulders floated across. This sea was not however, like Lyell’s, the result of a secondary accident, but arose, encircled and walled in by mountains, on the last upheaving of the Alps. Its waters overflowing their boundary at the lowest points, according to Wissmann enlarged the passages of discharge, which giving vent to the waters, gradually lowered and finally emptied the sea, leaving the valley of the Rhone and of the Rhine as a relic. If, however, hypotheses of at least equal probability have been rejected either as depending too much on supposititious data, or as being imperfect explanations of the phenomena, there seems no greater reason for admitting these. Such accidents as those suggested by Mr Lyell have indeed occurred in the Alpine regions; rivers have been dammed up either by falling hill-sides or by falling masses of ice, and on bursting through these obstacles, have poured down in fearful destruction on the plain below. But how diminutive are such catastrophes in comparison to that which must have attended on the dispersion of the Alpine boulders! and although the lake of Wissmann’s hypothesis is sufficiently extensive to transport the boulders through a very wide space, it is insufficient to account for those in Franche-compté; whilst, if we suppose with him that the last elevation of the Alps was prior to the deposition of the Molasse, it seems improbable that all the great openings of discharge, or vallies, should have been formed since that period. Must we then turn from these explanations, and again suppose great relative changes of altitude by vast upheavings of mountain chains in comparatively recent times, giving rise to diluvial waves, or, as supposed by De Beaumont, such upheavings being accompanied by a sudden rise of temperature, to the sudden melting of huge masses of snow and ice, and to powerful torrents resulting from it? Are we in short to appeal with Kapp to the testimony of the Chinese Annals, elucidated by Edward Biot of the French Academy, for evidence of such changes? In them, mention is indeed made at dates of 2400 and 3300 years before our era, of the elevation of two mighty chains of mountains, by which an ancient sea was raised up and became the present Marsh of Gobi, having been drained by an arm of the Yellow River, or through the valley of Tsischi, and at the same time the course of the Yellow and many other rivers were greatly changed. But, truly curious as such documents undoubtedly are, and worthy of the most attentive research in order to ascertain what support can really be given to geological theories by historical evidence, they could not be received as conclusive in respect to the face of Europe, unless something like a chain of deductive reasoning from observed facts could be adduced in support of them. What, then, is the state of the case? Must we reject the ice-transporting theory as insufficient, and stand in despair of ever finding a clue to our difficulties? Far from it: the very difficulty itself points to the true explanation. The northern or Scandinavian boulders are not mixed with the Alpine on the low grounds at the base of the Jura, and this circumstance shows us that there was a limit to the space over which these boulders were transported, and that limit was, probably, the result of the elevation at which the ocean then stood. Whilst, then, this ancient ocean was conveying from the Scandinavian peaks its falling glaciers loaded with fragments of rocks, the glaciers of the Alps were conveying over the ice-covered land the fragments of its broken pinnacles. Such a union of the two modes of transport, combined with sea currents, seems at once consistent with reason and efficient in explanation; for example, it explains the difficulty experienced in understanding the ancient glaciers of the northern face of our Dublin mountains, where we see limestone gravel and fragments of red sandstone accumulated against their base up to a certain point where they end abruptly, and gravel of primitive rocks begins. The limestone gravel and fragments of sandstone may have been conveyed there, and heaped up by the pressure of drifting ice, whilst the descending glacier conveyed primitive fragments, and pushed up before it into a heap the limestone gravel. We have therefore now come to the consideration of the glacier theory, which, propounded and explained by Agassiz, has assumed not merely a character of sublimity, but of demonstration. This I shall enter upon in another article, to which I shall also defer some necessary remarks on the supposed causes of that great and general refrigeration which Agassiz assumes, and the facts support. But even now I cannot refrain from answering a question which may possibly be asked by some, Why do you place so abstruse and difficult a subject before the readers of a popular work? I do so, because, though assuredly of no easy solution, the boulder question is one replete with interest, and calculated to excite the attention of many who perhaps never before thought that in those time-worn stones was matter to exercise the deepest reflection of the philosopher. But this is not all. To follow up the theories of the astronomer, instruments, and “appliances to boot,” are necessary, which few can possess; but to seek for geological data, the inquirer needs only health, his hammer, and his bag. When, therefore, as so powerfully urged by Mr Patterson, in his beautiful address to the Natural History Society of Belfast, our national system of education shall include within it an elementary course of natural history, we may hope to see in each of its trained schoolmasters not a “village Hampden,” but a “village White” or “village Saussure,” and in each locality around him a group of young and ardent naturalists growing up with a taste and enthusiasm for scientific research which not only will infuse happiness over their own breasts, but multiply the data for correct deductions. And in what branch of geological inquiry is such a multiplication of materials more required than in the one we have been discussing? Happy times, then, for science, morality, and religion, when a taste for research shall have been budded on the earliest shoot of man’s intelligence!

J. E. P.

Cruelty to Animals.—Though civilization may in some degree abate the native ferocity which prompts men to torture the brute creation, it can never quite extirpate it. The most polished are not ashamed to be pleased with scenes of barbarity, and, to the disgrace of human nature, to dignify them with the name of sports. They arm cocks with artificial weapons, which nature had kindly denied to their malevolence, and with shouts of applause and triumph see them plunge them into each other’s hearts; they view with delight the trembling deer and defenceless hare, flying for hours in the utmost agonies of terror and despair, and at last sinking under fatigue, devoured by their merciless pursuers. They see with joy the beautiful pheasant and harmless partridge drop from their flight, weltering in their blood, or perhaps perishing with wounds and hunger, under the cover of some friendly thicket to which they have in vain retreated for safety; they triumph over the unsuspecting fish, whom they have decoyed by an insidious pretence of feeding, and drag him from his native element by a hook fixed to and tearing out his entrails; and to add to all this, they spare neither labour nor expense to preserve and propagate these innocent animals, for no other, and but to multiply the objects of their persecution. What name should we bestow on a superior being whose whole endeavours were employed and whose whole pleasure consisted in terrifying, ensnaring, tormenting, and destroying mankind?—whose superior faculties were exerted in fomenting animosity amongst them, in contriving engines of destruction, and inciting them to use them in maiming and murdering each other?—whose power over them was employed in assisting the rapacious, deceiving the simple, and oppressing the innocent?—who, without provocation or advantage, should continue from day to day, void of all pity and remorse, thus to torment mankind for diversion, and at the same time endeavour with the utmost care to preserve their lives, and to propagate their species, in order to increase the number of victims devoted to his malevolence, and be delighted in proportion to the miseries which he occasioned? I say, what name detestable enough could we find for such a being? Yet if we impartially consider the case, and our intermediate situation, we must acknowledge, that, with regard to inferior animals, just such a being is a sportsman.—Disquisitions on Several Subjects, by Soame Jenyns.