New Red Sandstone

“ I am in a district of the New Red Sandstone, and as far as my eye can reach I see towering cliffs of a kindred formation, wheeling round or jutting out in foxy-coloured masses, while the innumerable points of shingle glow like an autumn stubble at their feet. ”

“ This is more especially true with respect to the second or Waterstone subdivision of the New red sandstone, the dark brown or pale red sandstones of which, with their interstratified marls and calcareous bands, are scarcely distinguishable by any lithological characters from similar beds in the Permian formation. There are, however, we believe, no brick-red sandstones like that of the Bunter, and scarcely any quartzose conglomerate to be found in the Permian formation ”

“ V. But the economic and practically useful, no less than the speculative or fanciful, form constituents of the new red sandstone formation. The strata are not only indented with impressions of strange and doubtful origin; they inclose, like those of the carboniferous system, treasures of the greatest value; and nature, [180] in ceasing to abound in one kind of product, has been no less exuberant in others, equally contributive to the comfort and convenience of man. ”

“ The fossil impressions which have been distinguished in various places in the new red sandstone are those of birds, frogs, turtles, lizards, fishes, mollusca, crustacea, worms, and zoophytes. Besides these, the impressions made by rain-drops, ripple-marks in the sand, coprolites or indurated remains of fæces of animals, and even impressions of vegetables, have been preserved and transmitted from a remote antiquity. No authentic human impressions have yet been established ”

“ These red deposits may be accounted for by the decomposition of gneiss and mica schist, which in the eastern Grampians of Scotland has produced a mass of detritus of precisely the same colour as the Old Red Sandstone.
It is a general fact, and one not yet accounted for, that scarcely any fossil remains are ever preserved in stratified rocks in which this oxide of iron abounds; and when we find fossils in the New or Old Red Sandstone in England, it is in the grey, and usually calcareous beds, that they occur. ”

“ 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. ”

“ Others are taken from local English provincial names, and remind us of the debt we owe to William Smith, by whom so many of them were first used—Lias, Gault, Crag, Cornbrash. Others of later date recognize an order of superposition as already established among formations—Old Red Sandstone, New Red Sandstone. By common consent it is admitted that names taken from the region where a formation or group of rocks is typically developed are best adapted for general use. Cambrian, Silurian, Devonian, Permian, Jurassic are of this class, and have been adopted all over the globe. ”

“ Geology.—All the islands of this group are built up entirely of Old Red Sandstone. As in the neighbouring mainland of Caithness, these rocks rest upon the metamorphic rocks of the eastern schists, as may be seen on Pomona, where a narrow strip is exposed between Stromness and Inganess, and again in the small island of Graemsay; they are represented by grey gneiss and granite. The upper division of the Old Red Sandstone is found only in Hoy, where it forms the Old Man and neighbouring cliffs on the N.W. coast. ”

“ The Upper Old Red Sandstone, composed of red sandstone and conglomerates, is only sparingly developed. The strata occur on the east shore between the Fallen Rocks and Corrie, and they appear along a narrow strip to the east and south of the lower division of the system, between Sannox Bay and Dougrie. ”

“ The shallow section, however, has been well wrought; and its suit of fossils is one of the finest, both from the great specific variety which they exhibit, and their excellent state of keeping, that the Upper Old Red Sandstone has anywhere furnished.
So great is the incoherency of the matrix, that we can dig into it with our chisels, unassisted by the hammer. It reminds us of the loose gravelly soil of an ancient graveyard, partially consolidated by a night's frost,—a resemblance still further borne out by the condition and appearance of its organic contents. ”

“ Measured against each other in time, their limits must disagree. On turning to the evidence, we find that it daily tends more and more to justify these a priori positions. Take, as an example, the Old Red Sandstone system. In the north of England this is represented by a single stratum of conglomerate. In Herefordshire, Worcestershire, and Shropshire, it expands into a series of strata from eight to ten thousand feet thick, made up of conglomerates, red, green, and white sandstones, red, green, and spotted marls, and concretionary limestones. ”

“ No positive evidence exists as to the condition of this region during the vast interval between the Old Red Sandstone and the older Secondary rocks. We can hardly believe it to have remained as land during all [Pg 140] that time, otherwise, the denudation, vast as it is, would probably have been still greater. Not improbably the region had become stationary at a base-level of erosion beneath the sea; that is, it lay too low to be effectively abraded by breaker-action, and too high to become the site of any important geological formation. ”

“ 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. ”

“ 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. ”

“ 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 ”

“ The Gaspé sandstones, as their name imports, are predominantly arenaceous, and often coarsely so, the sandstones being frequently composed of large grains and studded with quartz-pebbles. Grey and buff are prevalent colours, but red beds also occur, more especially in the upper portion. There are also interstratified shaly beds, sometimes occurring in groups of considerable thickness, and associated with fine-grained and laminated argillaceous sandstone, the whole having in many places the lithological aspect of the coal-measures. ”

“ In a depression of the granitic or hypogene rocks in the States of Massachusetts and Connecticut, strata of red sandstone, shale, and conglomerate are found occupying an area more than 150 miles in length from north to south, and about 5 to 10 miles in breadth, the beds dipping to the eastward at angles varying from 5 to 50 degrees. The extreme inclination of 50 degrees is rare, and only observed in the neighbourhood of masses of trap which have been intruded into the red sandstone while it was forming, or before the newer parts of the deposit had been completed. ”

“ Moreover, in a precipitous part of the ravine of Las Bocas, a red sandstone is distinctly seen to overlie a thick bed of pale mud, also quite like the Pampean formation, abounding with concretions of true tosca-rock. This sandstone extends over many miles of country: it is as red as the brightest volcanic scoriæ; it sometimes passes into a coarse red conglomerate composed of the underlying primary rocks; and often passes into a soft white sandstone with red streaks. ”

“ The sandstones are generally free gritstones made up of grains of quartz and felspar, with a little mica; and when in solid beds forming durable building stones. The shales are mud beds, in which alumina predominates, forming, when disintegrated, a tough clay sub-soil, several of which are loaded with carbonaceous matter; but there is no hard line between a sandstone and a shale, for slaty sandstones, by a larger admixture of argillaceous matter, become a kind of shale; and even some shales are so carbonaceous as to be combustible. The limestones are mostly tolerably pure carbonate of lime ”

“ 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. ”

“ As soon as we ascend the mountains, we meet with a slaty sand-stone of various compactness, as it possesses more or less iron, often forming an excellent iron ore. A variety of this iron ore has been lately turned to a good use, in the manufacture of a red paint, near Knoxville, Tennessee. Different varieties of this sandstone possess different qualities. It is converted by the inhabitants into millstones, grindstones, and whetstones. ”

“ The sandstone pillars generally taper from the base upwards to a short distance from the tops, which are flattened out or surmounted by slabs or blocks of sandstone 90 of fantastic outline, and they are called by names derived from fancied likenesses to animals, birds, and men. The juxtaposition of the most brilliantly hued, dazzling-red blocks and strata, with masses of the same material of milky whiteness, gives the impression that the scene is the work of human hands; it seems too quaint and artificial for the hand of Nature, to which alone it is due ”

“ This rock, as we have already remarked, is constantly accompanied by gypsum and muriate of soda. The red and somewhat argillaceous soil which results from its disintegration is far more fertile than that of the gravelly plains of the Platte, being often covered with a luxuriant growth of grasses, and affording pasturage to great numbers of herbivorous animals.
About one hundred and fifty miles west from the confluence of the Arkansa and Canadian, this red sandstone is discontinued, being succeeded, or perhaps overlaid by an extensive coal formation. ”