IlEfrSANDSTONE FORMATION. 



KED-SANDSTONE FORMATION. 



regard the analoey of the geological nomenclature mott generally mod, 

 tbu Utter MOM will appear too inconvenient to be adopted ; a* sub- 

 stitutes we bare the 1'cecilitic System, from the ration* colours of 

 the component mum ; ai:d the Saliferous System, from ita frequently 

 containing salt. 



Sandttonei or OriUtones, generally speaking, consist of abraded and 

 worn piroei of quarts, felspar, mica, and other minerals, such as 

 commonly occur in granite, gueifs, or mica-schist, and other rocks 

 associated with these. The siie of these pieces is sometimes such as 

 cause the man to deserre the title of conglomerate (as part of the 

 millstone-grit of Derbyshire), and sometimes the grains are so fine 

 and confluent, that the maas is not unlike some sorts of quartz rock 

 (aa the ganister of the Yorkshire coal-field). In regard to induration, 

 there is every degree from uccoherent sand, through friable and 

 argillaceous sandstone*, to compact grits and indurated quartzore 

 rock*. In colours they admit of every shade from wink-ness, through 

 gray tints by carbonaceous admixture, through yellow and brown 

 hues by admixture of carbonate and oxide of iron, and through rede, 

 blues, and purples of different kinds by diffusion of oxides of iron, 

 manganese, Ac. 



In this most complex series of detrital deposits, red-sandstones 

 present some remarkable diameters when regarded as to the nature 

 and diffusion of red colour, the association of this with other tints, 

 the relation of their hues to organic life, and to other geological 



Red sandstones occur in the basin of the Allierin France, in tertiary 

 strata ; in the plastic clay group of the Isle of Wight ; generally in 

 the strata below the lias and above the coal ; in the upper parts of 

 the coal formation of Derbyshire and Lancashire ; in the millstone- 

 grit series of Lancashire; in the mountain limestone of the north of 

 Kngland ; generally in the strata called old red-sandrtone, above the 

 stnta of the Silurian districts ; in the midst of the green and purple 

 slates of north and couth Devon ; in the midst of older rocks in the 

 Lamiuermuir, Cavan, and Longmynd ridges; but the most perfect 

 and abundant types are in those parts of the series which lie above 

 and below the carboniferous rocks, and constitute the Mew and Old 

 Red-Sandstone groups. 



The essential peculiarity of these reddened rocks is apparently a 

 general diffusion in their mass, snd especially round their constituent 

 grains of quartz, of red peioxide of iron (with nUo often some oxide 

 of manganese ?). If by means of muriatic acid the iron be removed 

 from the re d sandstone of Manchester, what remains is a mass of 

 mostly white and even translucent quartz grain*, which had been 

 invested by the red oxide of iron. Singularly enough, amidst a great 

 icriea of such red-sandstones and red-clay*, nothing is more common 

 and even characteristic than to find oval, round, or irregular patches 

 of light-green colours, apparently due to the protoxide of the same 

 metal. Nor is it at all rare to find perfectly white bands alternating 

 with red or green (tripes; and this applies almost equally to the 

 sandstones, clayt, gypsum-bands, and salt layers. 



A very remarkable and general fact observed in studying these red 

 rock* is the paucity of the remains of animals of every grade. 



The explanation of this fact, which seems most probable, is that 

 water in which by any cause abundance of peroxide cf iron has been 

 diffused, is rendered thereby unsuitable for the due performance of 

 the vital functions of aquatic creatures, especially such as take the 

 water into their bodiea for respiration, or are nourished by the flowing 

 of currents to the mouth. 



The Ust point on which it seems here necessary to remark is the 

 fitqurnt concurrence of red-rand*tonea aud clays, fibrous and lamellar 

 rypsam, fibrous and lamellar rock rait Most of the rock-salt, of 

 Europe at least, is associated with red earthy deposit* ; but there are 

 great exception*, as at Halzl/urg and Wiclicska, This frequent con 

 c unvote will be found of great importance in reasoning on the 

 |h)tic*l agencies whereby the peculiarities of red sandstones were 



As buildirg materials, few of the red-sand itonea are to be recom- 

 minded, and even the white layers which accompany them are 

 leldom of much value. The cathedrals of Carlisle and Cheater, and 

 (he noble old churches of Coventry, offer a striking warning to the 

 architect ; though on the other band, part of the ancient wall of 

 I'enrilh Cattle, (till rtacding i>nd in good preservation, shows that 

 even among these justly iu>[ ect< d strata, acme portions, either by 

 their freedom from talt, or tome other cause, are to be excepted from 



The tetm Red Sandstone is more especially applied to two forma- 

 tions, the Old Red Sandstone, or Devonian [OLD RED-SAKMTONI ,and 

 ibe New Id d-San<Uti>ne Itocka. The Utter are also rometimes called 

 KsliferoM, on account of tie talt they contain, and they are alac 

 called Triauic. 



" It is in Cheshire and the southern part of Lancnrhire, nd the 

 northern part of BbropaUn, which together form an extensive and 

 rich plain, wateicd by the I<e, the Mtrtey, and the Wiaver, that the 

 nppeimoat tda of the New Hed-Sanrl.tone are chiefly developed ; and 

 by a minute examination of the*e bed*, snd those of Warwickshire, 

 the raliferons marls have been identified with the uppermost strata of 

 the foreign Triaraic Ky >b m. Throughout thU range the beds are nearly 

 horizontal, the dip rarely exceeding ten <T twelve degree*, and being 



constantly towards the east, or a few degrees north or south of that 

 point. They are however affected by some important faults. The 

 whole district abounds with salt-springs, which are more especially 

 plentiful in Cheshire; and in that county also there occur extensive 

 masses of rock-salt in a solid state, their total thickness amounting 

 to not leas than sixty feet. These alternate with beds of gypsum ; 

 with numerous bands of indurated cUy of a blue, red, or brown 

 colour; and with saudntout a, frequently marly, and of a red colour. 



" The red-marl district, with brine springs, is continued southward 

 into Worcestershire, and northward into the valley of the Iden, and 

 the same part of the formation extends also eastward, occupying for 

 the most part the plains through which the 11 umber and its tributaries 

 make their way to the German Ocean. In Somersetshire anil Devon- 

 shire similar sandstones recur, and lie uncouformably, overlapping the 

 inclined edges of the older rocks, or abutting against them, but uni- 

 formly composed of the same materials, remarkable throughout for 

 the ochraceous colour pervading them. Between Sidmouth and 

 Seaton, in Devonshire, the rrd marls contain gypsum in abundance ; 

 and near Teignmouth the cliffs, which are of considerable bright, 

 consist of alternations of argillaceous beds of sandstone and of 

 conglomerate. 



" The beds which are lowest in position of the upper new red- 

 sandstone are chiefly found in the middle of England, and consist of 

 thick masses of whitish soft sandstone. In some places (as in Staf- 

 fordshire) these are surmounted by conglomerates, composed of 

 rounded pebbles of quartz rock, and other fragments, chiefly of 

 Silurian rocks nnd old red-sandstone. The total thickness of this 

 port of the formation is considerable, but has not been accurately 

 calculated. It is only to be distinguished from the overlying sali- 

 feroue marls by small differences of mineral character." (Ansted.) 



Viewed on the great scale, the New Ked-Sandstone system of rocks 

 U one of the most varied and interesting we are acquainted with. 

 There are peculiarities iu ita limestones, sandstones, aud clays, as well 

 as in its gypseous and salt deposits ; the occurrence and nature of 

 iU organic contents, and the relation which it bears altogether to 

 earlier and later classes of rocks, are worthy of careful study. 



Sulphate of lime is fouud perhaps as frequently and under almost 

 as many curious circumstances in the stratified rocks, as carbonate 

 of lime, in mealy aggregations, acicular prisms, broadly foliated 

 crystals (selenitc). fibrous mosses and beds, and maruioroid or alabas- 

 trine rocks. It lies in strata of almost every age, and is not absent 

 from diluvial, alluvial, and recent deposits. The mode of its occur- 

 rence is in a considerable degree characteristic of each particular 

 mineral type. While long prismatic crystals appear in cavities of 

 shells and in recent excavations (as in the gallery of Felling Colliery, 

 Newcastle), the solitary broad flaky crystals of aelenite abound iu 

 blue-clays of the tertiary and secondary series (which receive their 

 colour from protoxide of iron), and the fibrous gypsum marks, spots, 

 and irregular lines in the red-clays (coloured by peroxide) of the S:ili- 

 ferous system, the fibres being (in agreement with a general law of 

 structures) arranged so as to lie at right angles to the broader surface; 

 which bound the mass. The marmoroid texture is most commonly 

 found in real however irregular beds, as at Montnmrtre, and in some 

 points near Fairburn in Yorkshire, on the line of the York and North- 

 Midland railway. At these places fibrous, marmoroid, and flaky sul- 

 phate of lime may be obtained in association. 



From what is known to take place at the present day, and from 

 appearances in the distribution of the gypsum and st-lenite in masses 

 of clay and cavities of shells, &c., it appears that in a great propor- 

 tion of cases these crystallised masses owe their origin to the processes 

 of segregation since the deposition of the earthy muses in which they 

 appear. In no other way is it at all conceivable or even possible that 

 the irregular masses of gypsum which appear in red-marl at Axmoutb, 

 Aust Passage, and the Trent's mouth could be formed. The marls iu 

 which they here lie were deposited as fine mud, and if we suppose 

 merely a slow extrication of the liquid, so that its contained salts 

 might remain, the arrangement of these salts in auch irregular masses 

 during crystallisation presents no particular difficulty. 



Salt shows itself in the Cheshire mines as either granular, broadly 

 laminated, or fibrous ; in gnat beds or minutely mixed with marls, 

 nearly as gypsum is, and probably in regard to its origin, similar 

 suppositions will apply, the solid beds (of limited extent however and 

 irregular area) being due to a great evaporation of liquid over the 

 previously-depoiited marls. That such water, in the case of rock-salt 

 generally, was derived from the sea, is almost certain, from the occur- 

 rence of iodine and bromine in the brine-springs connected with them. 

 (Daubeny's Memoir in ' 1'hil. Trans.') But it does not follow that the 

 area in which the call was found was, at the time of its formation, or 

 for some time previously or subsequently, connected with the sea. 

 Lagoons may have been the theatre of the evaporation supposed, and 

 earthy sediments, such aa occur in Cheshire and 1'oland, may have 

 been drifted in by fresh-waters or the sea, according to circumstances, 

 and it is not difficult to imagine a repetition of the processes, such 

 as might produce the two great beds of rock-jolt in Cheshire. It is 

 not known that organic remains of any kind accompany the salt of 

 Cheshire, but this is almost true of the whole range of the red-marls, 

 in which these deposits lie. 



We find, then, associated together, abundauce of red-oxide of iron 



