Old Red Sandstone

“ NEW RED SANDSTONE. A large series of reddish-colored loams, shales, and sandstones, occurring between the Carboniferous and the Middle Triassic formations, were grouped together under this name, in contradistinction to the Old Red Sandstone group, which lies below the coal measures, and has a similar mineral structure. ”

“ It occupies the same place, and belongs to the same period, as those superior beds of the Lower Old Red Sandstone which are so largely developed in the cliffs of Dunnet Head in Caithness, and of Tarbet Ness in Ross-shire, and which were at one time regarded as forming, north of the Grampians, the analogue of the New Red Sandstone. I paced it across the strata this morning, in the line of the ravine, and found its thickness over the upper fish-beds, though I was far from reaching its superior layers, which are buried here in the sea, to be rather more than five hundred feet. ”

“ The surrounding country is composed chiefly of Silurian schists, in which there is deeply inlaid a detached strip of mouldering Old Red Sandstone, considerably more than twenty miles in length, and that varies from two to three miles in breadth. It seems to have been let down into the more ancient formation,—like the keystone of a bridge into the ringstones of the arch when the work is in the act of being completed,—during some of those terrible convulsions which cracked and rent the earth's crust, as if it had been an earthen pipkin brought to a red heat and then plunged into cold water. ”

“ A short walk over a grassy down gives on to an outcrop of very dirty sandstone, which in the excessive innocence of his heart the visitor naturally takes to be the coal lying neatly on the surface. Up to this sandstone the path seems to be made of crushed sugar, so white and shiny is the quartz. Over the brow of the down comes in sight the old familiar pit-head wheel, spinning for the dear life, and the eye loses itself in a maze of pumping sheds, red-tiled, mud-walled miners' huts, dotted all over the landscape, and railway lines that run on every kind of gradient. ”

“ Its uneven plain of Old Red Sandstone leans, at a few miles' distance, against dark Highland hills of schistose gneiss, that, at the line where they join on to the green Lowlands, are low and tame, but [Pg 197] sweep upwards into an alpine region, where the old Scandinavian flora of the country—that flora which alone flourished in the times of its boulder clay—still maintains its place against the Germanic invaders which cover the lower grounds, as the Celt of old used to maintain exactly the same ground against the Saxon. ”

“ If this be the case, what stratum, if not the old red sandstone, should be seen emerging from beneath that secondary along its south-eastern margin? We will not, however, contend for the name. It is sufficient for our purpose to state, that the sandstone so abundant in all the principal ridges accessory to the Alleghany on the east, has the character of a rock belonging to the transition class of the Wernerians; that is, its {330} strata have a somewhat regular dip and inclination; it contains no beds of bituminous coal, though many of anthracite, and few organised remains. ”

“ We discover the still little known but highly interesting fossils of the Old Red Sandstone in one deposition; we find the beautifully preserved shells and lignites of the lias in another. There are the remains of two several creations at once before us. The shore, too, is heaped with rolled fragments of almost every variety of rock,—basalts, ironstones, hypersthenes, porphyries, bituminous shales, and micaceous schists. In short, the young geologist, had he all Europe before him, could hardly choose for himself a better field. ”

“ Nowhere can the details of the Old Red Sandstone volcanic rocks be more conveniently studied than along the coast-section in this district from the Red Head to Stonehaven. The rocks have not only been cut into vertical cliffs, but along many parts of the shore they have been also laid bare in ground-plan, so that a complete dissection of them is presented to the geologist. ”

“ I had thought over the matter many a time and oft when I should have been asleep,—for it is marvellous how questions of the kind grow upon a man; and now, selecting as a hopeful scene of inquiry the splendid section under the Northern Sutor, I set myself doggedly to determine whether the Old Red Sandstone in this part of the country has not at least its two storeys of organic remains, each of which had been equally a scene of sudden mortality. I was entirely successful. The lower ichthyolite bed occurs exactly one hundred and fourteen feet over the great Conglomerate ”

“ Sandstone, Old Red.—Composition of the more distant ranges on the Morumbidgee. Forms abrupt precipices over the river flats; of sterile appearance, and covered with Banksias and scrub.
Mica Slate.—Colour dark brown, approaching red; mica glittering. The hills enclosing Pondebadgery Plain at the gorge of the valley of the Morumbidgee, are composed of this rock. They are succeeded by
Sandstone.—Which rises abruptly from the river in perpendicular cliffs, of 145 feet in height. ”

“ Then Abner Dean of Angel's raised a point of order, when A chunk of old red sandstone took him in the abdomen, And he smiled a kind of sickly smile, and curled up on the floor, And the subsequent proceedings interested him no more. ”

“ Whoever has rambled much in a coal-country, scrambling through briars and brambles in old quarries, or threading his way among the rocks of river-courses, must often have noticed, on the exposed surface of sandstone blocks, dark ribbon-like bands fretted over with little diamond-shaped knobs. They are so common in some districts, that you can scarcely light upon a piece of sandstone which does not show one or more. ”

“ They were the footprints of the sand-piper, a bird of which he saw flights daily running along the water's edge, and often leaving thirty or more similar impressions in a straight line, parallel to the borders of the estuary. He picked up some slabs of this dried mud, and splitting one of them up, found a surface within which bore two lines of the same kind of footprints. Here is an example before our living eyes, of the processes concerned in producing and preserving the fossil footprints of the New Red Sandstone. ”

“ That this is merely surface coloring is shown by the fact that hydro-chloric acid will discharge the color and leave the grains translucent. Unfortunately the most brilliantly colored stone is not the most durable, and it so happens that these brilliant red sandstones are often composed of exceedingly rounded grains. Also some of the very red sandstone has an interfilling of a loose argillaceous irony matter detrimental to the stone as a building stone. The most durable of the red sandstones are those having a paler or grayer hue, like those of Woolton, Everton, and Runcorn. ”