Roc

“ We were accompanied by a few soldiers, who it turned out did not know the way, and having ridden for an hour and a half up a narrow gorge with wild figs, wild date, and fan palms growing around us, and really magnificent cliffs 700 to 800 feet high on either side of us, reddish in colour and with fossils in the limestone strata, a truly fearful and awe-inspiring place, we suddenly came to an abrupt termination of our valley, having wormed ourselves along, chiefly on foot, and found that unless Sindbad's roc came to our assistance we could not possibly get out of it. ”

“ Roque drives briskly at first, a slight breeze refreshes us, and we think the road better than is usual. But wait a bit, and we come to what seems an unworked quarry of coral rock, with no perceptible way over it, and Roque still goes on, slowly indeed, but without stop or remark. The strong horses climb the rough and slippery rocks, dragging the strong volante after them. ”

“ The Rhone has lowered its bed a thousand feet since the liquid stone flowed, and torrents have cut through lava and limestone, fashioning deep and even broad valleys. Next, the weather ate into the flanks where the stone was soft, undermined the basalt, that came down for lack of support in huge masses. Not only so, but man from the remotest period has burrowed into the rock to form habitations for himself. ”

“ The cliffs on each side were steep and abrupt, pierced with caverns, and channeled with water-courses, and in the bottom of the valley there were large rocks of fantastic form, percolated by rain, and tinted red, gray, orange-color, and lavender, relieved by black and white. On the rock-ledges above us there were scanty crops of barley, wheat, and lentiles, and olive and fig trees appeared again in small groups. Flocks of goats and larger cattle were being led out to seek for pasture by rather desperate-looking herdsmen, well armed. ”

“ The paths which lead to it out of the valley of the Rhone, rising at first in steep circles among the walnut trees, like winding stairs among the pillars of a Gothic tower, retire over the shoulders of the hills into a valley almost unknown, but thickly inhabited by an industrious and patient population. Along the ridges of the rocks, smoothed by old glaciers into long, dark, billowy swellings, like the backs of plunging dolphins, the peasant watches the slow colouring of the tufts of moss and roots of herb, which little by little gather a feeble soil over the iron substance ”

“ I have already alluded to one limited area where various rocks exist, distinctly different from the prevalent types in the Lewisian gneiss. In the area which is traversed by the long valley of Loch Maree in western Rosshire, there occur clay-slates, fine mica schists, graphitic schists, and saccharoid limestones. These rocks remind us of some of the prevalent members of a series of metamorphosed sediments. The minerals enclosed in the marbles are just such as might be expected in the metamorphic aureole of a granite boss, piercing limestone. ”

“ The time before dinner is occupied in an exploration of the wildly picturesque gorge, with its winding foot-bridge built alongside the cliffs, over yawning chasms, around jutting bowlders that rise to such a height that the sky seems like a strip of blue ribbon suspended high above our heads. At the bottom of the gorge a mountain torrent, springing from some unknown nook way up in the mountain, comes rushing and tumbling down over the jagged rocks, foaming and whirling, and dashing its spray high in the air, as it hurries along to join the Rhone. ”

“ The waves break on these huge masses without intermission, with a hollow and alternating roar, or rise up in sheets of foam, which besprinkle their hoary fronts. These masses of mountains—for they are too large to be called rocks—are piled and heaped together in such numbers, that they form an innumerable number of narrow havens, of profound caverns, of sounding grottoes, of gloomy fissures—of which the children of some of the neighbouring fishermen alone know the windings and the issues. ”

“ It is impossible to lose the impression that some freak of human or superhuman fancy gave the stones their quaint grouping. Between the ridges are shallow hollows, terminating towards the west in deep, rocky clefts, and opening on the river in crescent-like coves, between the jaggy headlands which tumble their boulders into its bed. High peaks, or rather conical piles of porphyry rock, rise here and there out of this sterile chaos. Toward the east, where the Nile winds away in a long chain of mazy curves, they form ranges and show compact walls and pinnacles. ”

“ The Rhone, the Po, the Nile, and many hundred minor streams and springs, pour annually into the Mediterranean large quantities of carbonate of lime, together with iron, magnesia, silica, alumina, sulphur, and other mineral ingredients in a state of chemical solution. To explain why the influx of this matter does not alter the composition of this sea has never been regarded as a difficulty; for it is known that calcareous rocks are forming in the delta of the Rhone, in the Adriatic, on the coast of Asia Minor, and in other localities. ”

“ Stony nature of its deposits.—That a great proportion, at least, of the new deposit in the delta of the Rhone consists of rock, and not of loose incoherent matter, is perfectly ascertained. In the Museum at Montpelier is a cannon taken up from the sea near the mouth of the river, imbedded in a crystalline calcareous rock. Large masses, also, are continually taken up of an arenaceous rock, cemented by calcareous matter, including multitudes of broken shells of recent species. ”

“ We have, therefore, to consider what must have been the ancient condition of a region subjected throughout vast periods of geological time to the utmost force of disintegrating agencies applied to a rock very liable to yield to them, and where, without reckoning the large proportion which must have been carried by rivers to the sea, we see such vast deposits of the disintegrated materials formed out of the same matrix. ”

“ The pebbles on the plain of Crau at the mouth of the Rhone, and those vast heaps brought from the Alps of Dauphiné by the Isère and the Durance, have one local origin; almost every valley of the Alps and the Grampians has served for the passage of a peculiar suite of broken rocks; only at one point of the Penine chain of England have the Cumbrian rocks been drifted to the drainage of the Humber. ”

“ The rugged forms and rocky faces characterizing those hills of mica slate which bound Loch Lomond, Loch Long, Loch Fyne, or Strath Fillan, have disappeared; the mountains assume a more uniform flowing line, their sides are more completely covered with herbage, and exhibit fewer denuded rocks; their summits are less serrated, and are almost the only parts which exhibit the naked rock, while at the same time they are strewed with heaps of fragments, a character from which the hills of mica slate are almost always free. ”

“ Metamorphic rocks appear in rugged hills near Morocco, and white limestone on the high Atlas. Glacial moraines may be seen on this range nearly 8,000 feet above the sea, forming gigantic ridges and mounds of porphyritic blocks, in some places damming up the ravines; and at the foot of Atlas are enormous mounds of bowlders. These mounds often-times rise 2,000 feet above the level of the plain, and according to Mr. Man were produced by glaciers. ”

“ The plain of Morocco rises 1,700 feet above the sea-level, and is covered with a tufaceous crust, from a few inches to three feet thick, which is burnt for lime near the city of Morocco. The underlying rock is of similar composition but not so hard, and is called by Mr. Man a "cream-colored limestone and gray marl of cretaceous or tertiary age." Midway between Mogador and Morocco are flat-topped hills 200 or 300 feet high, covered with tabular masses of chalcedony. ”

“ In these parts of our country they form the surface-rock, and whether they have been always raised beyond the reach of sedimentary deposit or have been scoured and relieved by frost and flood of superincumbent strata, whether their present extent is conterminous with their limits, as once revealed above the level of primeval seas, or whether shrunken by subsidence and partially obliterated by later formations, they are at any rate outcrops of the vast bedding on which ocean and continent alike repose. ”

“ For all through the chine of England, and in a part of Ireland too, there lies upon the top of the limestone a hard gritty rock, in some places three thousand feet thick, which is commonly called “the mill-stone grit.” And above that again the coal begins. Now to make that 3000 feet of hard rock, what must have happened? The sea-bottom must have sunk, slowly no doubt, carrying the coral-reefs down with it, 3000 feet at least. And meanwhile sand and mud, made from the wearing away of the old lands in the North must have settled down upon it. ”

“ To proceed then, Cork seems to be by the transverse constitution of the pores, a kind of Fungus or Mushrome, for the pores lie like so many Rays tending from the center, or pith of the tree, outwards; so that if you cut off a piece from a board of Cork transversly, to the flat of it, you will, as it were, split the pores, and they will appear just as they are express’d in the Figure B of the XI. Scheme. ”

“ Entire Northern Africa, as far as the Sahara and the Falls of the Nile, consists of sedimentary ground, which never can have furnished metals; but in the interior we find old rock—granite, gneiss, and hornblende—and there the auriferous alluvial soil had been formed ”

“ Geology.—The Atlas Mountains, which are built up of a series of ridges rising to 12,000 ft. to the east of Morocco, form the backbone of the country. The central and highest portions consist of slates, crystalline limestones and schists of Archean, Pre-Cambrian and possibly of Cambrian ages. ”

“ To do this the more intelligently, we shall speak briefly first of the characteristics and deposits of the Diluvial and later prehistoric periods, and then of the human remains therein found.
The Drift or Diluvial Deposits.—The bottom-lands of our new valleys, of the Rhine, for example, chiefly consist of widely-extended deposits of loam, sand, gravel, and rocks, evidently brought from considerable distances by some vast current that once covered the lowlands, and even lesser hills ”

“ The most convenient subdivision for our present purpose, however, is that which proceeds upon the origin and mode of occurrence of the trap-rocks. Viewed thus, they resolve themselves into two great groups, the intrusive and contemporaneous, both of which contain greenstones, basalts, &c.,—the sole distinction between those of the one class and those of the other, being the relation of age and mode of occurrence which they bear to the surrounding rocks. ”

“ At a subsequent period the waters have excavated deep valleys, cutting down into the lacustrine rock-marble many hundred feet; and, at a newer epoch, anterior to the authentic history of Europe, new craters have opened, and fresh streams of lava have run down [Pg 100] the existing valleys. Even in the Tertiary period we have thus a series of demonstrative proofs of a long succession of physical events, each of which required a long lapse of ages for its elaboration.
"Again, as we pass downwards from the bottom Tertiary beds to the Chalk, we instantly find new types of organic life. ”

“ Laborious and scientific men have been at the pains to calculate the gradual increase of some of these now proceeding deposits,—such as the Deltas, in course of formation at the mouth of the Nile, and at the gorges of the Ganges; and they find that the progress of the depth of increase is exceedingly small,—probably not more than a foot in many years. ”

“ There is, however, some very good soil. We arrived on the banks of the Bâ-fing (the black river) so called because its bed consists of enormous rocks of black granite. Some of these rocks are pointed and very sharp, so that they often cut the feet of the negroes in crossing the river. The Bâ-fing is the principal tributary of the Senegal: it runs from south to north among the mountains. The masses of granite, of which its bed is composed, form several islets. Its current is astonishingly rapid and white with foam, which I supposed to be occasioned by some cataract. ”

“ Throughout the whole of Austral Africa, comprising Cape Colony, Kafirland, Natal, the Basuto, Zulu, and Dutch territories, the general geological substratum is constituted by granitic rocks, which underlie all the other formations of this region. By their incessant erosive action the running waters have everywhere exposed the lower granitic foundation and the sedimentary strata deposited on the primitive crystalline rocks. ”

“ Such examples, however, merely show that where a basin is so limited in size that the detritus is derived chiefly or exclusively from one formation, the prevailing rock will impart its colour and composition in a very decided manner to the loam; whereas, in the basin of a great river which has many tributaries, the loam will consist of a mixture of almost every variety of rock, and will therefore exhibit an average result nearly the same in all countries. ”

“ The rock here rises in perpendicular rugged cliffs of coral, with a number of rude square excavations on its face, which, at first sight, appear to have been worn by the elements, but on examination shew evident traces of art. Most of these caves are closed up by a wall of loose stones, but in one, of which the mouth was open, several human bones were found lying amongst the sand. ”