CHAPTER IX.GEOLOGICAL STRUCTURE OF FIFESHIRE—DIVISIONS OF THE COAL-FIELD.
The general remarks on the coal deposit, in which we have been led to indulge in the two last chapters, may be verified by, as they all receive the most ample illustrations from, the admirable arrangement, position, and distribution of the metals in the counties of Fife, Clackmannan, Stirling, Lanark, and Renfrew, which are extensions of one great basin. Fifeshire alone contains an epitome of the system, divided as it is into numerous compartments, the encrinital limestone cropping out and marking their several boundaries. Indeed, the whole series of the carboniferous rocks are here laid open for examination on every hill-side, in the numerous ravines which intersect the district, and along the eastern and southern coast-lines. Approaching the coal-field from the north, a panoramic section at once fills the eye, and will rivet the attention, as, stepping from the strata of the antecedent epoch, you find, in immediate superposition as well as contrast of color, the multiplied and more diversified reliquiæ of the coal-measures.
The eruptive rocks will also be here studied to great advantage, where they have played no insignificant part in giving shape and outline to the landscape, and in laying open the inclosed minerals. It is impossible to convey any adequate idea, in mere description, of the marvelous display of plutonic action of which this peninsula has once been the theater: subterranean movements crushing and grinding into fragments the solid strata, parting and heaving them asunder, or crumpling into complicated folds the tougher and more unyielding beds, as if it had been some fabric of manufacture tossed and twisted by the wind. The bituminous breccia at Pettycur, Elie, Balcarras Den, and which appears againat the Rock and Spindle near St. Andrews, affords a remarkable instance of the action of the intrusive rocks in breaking, and transmuting into a composite paste, the series of beds constituting the coal-measures, in which every one of the strata has its representative in fragments, from the size of a garden pea to masses a foot in diameter or even upward. The storm lifts the ocean into lofty curling billows, leaving long narrow troughs and frightful yawning chasms beneath. Here, in like manner, and all over the surface, the crust has been broken up, and the minerals tossed about, or agitated like wreck upon the waves, and, upon subsiding, have been cast into the form of ridges, or broad tabular masses. The ridges, with their serrated outcrops, in the interior of the county, have been gradually rounded off and covered with soil; while, by the shore, they still present the effects of the violent commotions to which they have been subjected, exposed and laid bare by the action of the sea, upon the lower levels of the disrupted strata. The Ochils, Lammermuirs, and Pentlands, were already above the waters, calmly contemplating the troubled scene, as an inner circle of basalt and greenstone hills arose—the Lomonds, Largo Law, the Binn, and Binnarty, on the north; Stirling rock, Corstorphine hill, Arthur’s Seat, Berwick Law, and the Bass, on the south—which were severally lifted into view, to be stationed as so many sentinels on the outposts of the field.
The coal metals shared in the general elevation of the hills, where they are either folded round their bases, or are depending, drapery-wise, from their tops. Thus the members of the inferior carboniferous series are raised about eleven hundred feet along the Lomond ridge, encompassing the east and west cones, and training westward by Binnarty and the Cleish hills. Largo and Kellie Laws have each their coal basins, of workable minerals, stretched along their eminences, and dipping toward the Teasses and Ceres basins. On the low grounds which skirt them on the south, the metals dip rapidly into the Forth, and are collected in various hollows or independent bands by the shore. The intermediate coal-fields, which occupy the center of the basin, are regulated in their strike and inclination by the dykes and outbursts of trap by which the strata have been invaded. A limestone traverses the county at right angles from north to south,emerging at Ravenscrag, which forms a line of demarkation betwixt the number of the coal seams on its opposite sides. The Lochgellic, Cowdenbeath, and Dunfermline basins, on the west, average about twelve to fourteen workable coal-bands, while on the east of the limestone, the Dysart, Wemyss, Teasses, and Ceres basins run from twenty to thirty-three of various quality and thickness. The Clackmannan coal-field recovers in numerical proportion, where there are twenty-four seams of coal, from two inches to nine feet thick, and two great slips, which raise the metals successively 700 and 1230 feet, as they abut against the Ochil range. In the Elgin basin there are twenty-seven beds of coal, with a thickness of fifty-six feet.
Fifeshire thus owes its diversified shape and contour, and access to all its vast mineral treasures, to the early disturbances by which it has been so thoroughly dislocated and furrowed. Every district has a section, separate and independent, of its own. The ground you tread on is, every foot of it, a cabinet of wonders—literally a necropolis, a city of the dead. Go where you will, chronicles of the olden time are before and around you, while everywhere—
“and at your sideRises a mountain-rock in rugged pride,And in that rock are shapes of shells, and formsOf creatures in old worlds.”
“and at your sideRises a mountain-rock in rugged pride,And in that rock are shapes of shells, and formsOf creatures in old worlds.”
“and at your sideRises a mountain-rock in rugged pride,And in that rock are shapes of shells, and formsOf creatures in old worlds.”
“and at your side
Rises a mountain-rock in rugged pride,
And in that rock are shapes of shells, and forms
Of creatures in old worlds.”
The cuttings of the Edinburgh and Perth Railway give excellent sections of the various minerals of the county, from the gray sandstone to the uppermost coverings of the coal-field. Entering Fifeshire from the west, your course lies deep among the detritus of the various members of the old red series already noticed. At the Newburgh Station, and under the cliffs of Clatchart, the gray sandstone and cornstone may be observed—the latter is regularly stratified; the former is embraced among the igneous rocks, broken, isolated, and inclined at every possible degree to the horizon. Clatchart Crag itself has been stirred to its foundations; the huge mass, reverberating now to the passage of other fires, rests on highly inclined beds of the gray sandstone; the black transverse dyke of basalt, a few hundred yards on the west, maybe conjectured to have been the instrument of upheaval, as in fancy we can still discern in the half-raised, half-suspended position of the rock, the enormous pressure required for its elevation.
The Lomonds and Cults hills are conspicuous objects in the landscape. The line traverses for miles the yellow sandstone and overlaying grits which form their base. Greenstone and augitic trap in both ranges cap the summits, bursting through the coal metals, and elevating the various beds of limestone. The encrinital limestone sweeps round the peaks of the Lomonds, filling up the intermediate plateau, in some places bare of herbage or any covering of soil, and the fossils are lying exposed on the surface fresh as when washed by the waves, about eleven hundred feet above their ancient sea-bottom. A vein of galena occurs on the south side of the hill, intersecting the limestone at right angles to the plain of stratification, and is described in the notices of the period of its discovery as rich in silver ore. But it has no great claim, we believe, to be regarded asargentiferous. Two similar veins traverse the county, one already noticed in Dura Den, and the other in the parish of Inverkeithing, situated among the same series of rocks, and having the same general line of bearing from nearly north-east by south-west. The lead ore in all of them is partly massive, and partly in regular hexahedral crystals. Lead, copper, cobalt, and silver are likewise found in the Ochil range, but in no great quantities, in the culminating heights betwixt Dollar, Bencleugh, and Dalmyat.
On approaching the river Leven at Markinch, the out-crop of the central coal-basin comes to the surface. After crossing the viaduct the line lies deep among the metals—a repetition of faults, upheavals, and depressions, where in succession the edges of the same beds are several times passed over. The dip is various, the strike generally to the south-east, and under the sea at Dysart the metals are wrought at the depth of several hundred feet.
The igneous rocks along the coast will not fail to call forth surprise and admiration, unrivaled as they probably are in the number of alternations with the deposits of the carboniferous series, and all the interesting phenomena which accompany theirintrusion. No description, indeed, can do justice to the interlacings and alternations presented of the two classes of rocks, so different in their origin, as those of the traps and coal-measures; where, through the agency of the former, the latter series are bent, twisted, re-united, altered, and lying at every angle betwixt the horizontal and perpendicular. Nearing Kirkaldy the coal is split up, and the fused matter injected between the layers, converting them into cinder. Within the distance of a mile, from Seaforth to Kinghorn, there are from forty to fifty alternations of the igneous and sedimentary rocks; and again, on the west, toward Pittycur, there is a recurrence of as many, with examples of the jointed columnar basalt reposing on sandstones rendered quartzose, or converted into chert, and on shales baked into brick. The outburst at the Burntisland terminus, in three parallel ridges, throws up the strata, inclining them toward the north, whence trending round the town they dip under the Binn-hill. Orrock-hill, lying immediately to the north-east of Binn-hill, furnishes a beautiful example of jointed basalt: the entire rock, three hundred feet high, and nearly a mile long, by half-a-mile in breadth, is composed of regularly constructed columns, which divide into concretionary masses from one to three feet in length, and presenting generally the pentagonal or hexagonal form. The columns are grouped into distinct clusters, which, inclining at various angles, impart to the exposed face of the rock a pleasing picturesque effect. The erosive action of water, or swell of the ocean tide, is all that is required here to shape another Staffa—“that wondrous dome”—out of these magnificent materials.
A fresh-water, or rather perhaps an estuary, limestone is an object of considerable geological interest in this locality, mixed up and altered in many places by the igneous matter. The best sections occur a little back from Pittycur harbor, and on the western slope of Binn-hill, where it is extensively quarried. Scales of fishes and other ichthyolites are very abundant: also innumerable microscopic shells, belonging to the order of entomostraca and the genus cypris. Several species of palæoniscus have been found in good preservation, namely, P. ariolatis, P. ornatissimus, and P. Robisoni. The Pygopteris Jamesoni and specimens of the Eurynotus and Crenatis have likewise been detected in the deposit.Vegetable remains are very plentiful, especially of the fern tribe and the lycopodiums: the impressions of the sphenopteris, of which there are several species, are extremely numerous, fresh, and beautiful. This limestone is of a dull, earthy aspect, acquired obviously from the bituminous matter diffused through the mass; not crystalline, though very compact in texture, and possessed of great hardness. Wardie beach, on the opposite shore, displays a bed having many points of resemblance, which abounds in nodular masses, inclosing coprolites and fishes; and inland, the celebrated Burdiehouse limestone is an extension of the Fifeshire deposit.
Thus varied and important is this small peninsula, a speck on the face of the globe, and affording so much room for speculation and detail. Inclosed between the estuaries of the Tay and Forth are to be found some of the most legible and remarkable chronicles of our planet’s history. Fifeshire has been stirred and upheaved all over, abounding in all the life-moving and plutonic energies of the carboniferous age. The vegetable and animal kingdoms supply a vast proportion of the materials of the sedimentary rocks, while the fires of the interior have mainly contributed to the production of the rest. Shall we look across the waters, and replace them, in imagination, by the former continuity of land, when the center of the coal-basin was raised above them, and their numerous islets were high and dry upon the surface? Certain it is, that the erupted matter so abundantly scattered along the shores and piled up in such masses landward, would leave room for subsidence, while the outgoing of the deposits on both sides shows such an affinity in quality and strike as to demonstrate an ancient union and geological connection.
Diplopterus—new species.
Diplopterus—new species.
Diplopterus—new species.