Popular Science Monthly/Volume 17/August 1880/Geology and History
|←Recent Original Work at Harvard||Popular Science Monthly Volume 17 August 1880 (1880)
Geology and History
By Charles Grant Blairfindie Allen
|The Cinchona-Forests of South America→|
THE science of human life has been the last to recognize that minute interaction of all the sciences which every other department of knowledge now readily admits. We allow at once that no man can be a good physiologist unless he possesses a previous acquaintance with anatomy and chemistry. The chemist, in turn, must know something of physics, while the physicist can not move a step until he calls in the mathematician to his aid. Astronomy long appeared to be an isolated study, requiring nothing more than geometrical and arithmetical skill 5 but spectrum analysis has lately shown us its intimate interdependence upon chemistry and experimental physics. Thus the whole circle of the sciences has become a continuous chain of cycles and epicycles, rather than a simple sequence of unconnected and independent principles.
History, however, still stands to a great extent outside the ever-widening sphere of physical philosophy. It is comparatively seldom that we see an historian like Dr. Curtius acknowledging the interaction of land and people upon one another's character and destiny. More often we find even the modern annalist writing in the spirit of Mr. Freeman, as though men and women formed the only factors in the historical problem, and the great physical powers of Nature counted for nothing in the game of human life. Yet a few simple instances will show at once the fallacy of such a view. If the ancestors of the Hellenic people had gone to the central plains of Russia instead of to the island-studded waters of the Ægean, could they ever have produced the magnificent Hellenic nationality with which we are familiar? Was not their navigation the direct result of their geographical position on the shores of an inland sea, intersected by jutting peninsulas, and bridged over by a constant succession of islands, each within full sight of its nearest neighbors? Was not their polity predetermined in large measure by the shape of their little mountain valleys, each open to the seaward in front and closed by a natural barrier of hills in the rear? Could their plastic genius have risen to the height of the Olympian Zeus and the Athene of Phidias if they had possessed no material for sculpture more tractable than the hard granite of Syene? While we allow that the Aryan blood of the Hellenes had much to do with the differences which mark them off from the Negroid Egyptians, can we doubt that Hellenic civilization would have been very different if the settlers of Attica had happened rather to occupy the valley of the Nile; and that the Egyptians would have become a race of enterprising sailors and foreign merchants if they had chanced to make their homes on the shores of the Cyclades and the Corinthian Gulf?
Or, again, let us look for a moment at Britain. Who can suppose that the destiny of our country has not been profoundly affected by the existence of great coal-fields beneath its surface? Even if we possessed no mineral wealth, it is probable that our geographical position would still have insured us a considerable commercial importance as the carriers of the civilized world. Britain happens to occupy the central point in the hemisphere of greatest land, and this fact, aided by its insular nature, could not fail to make it a great mercantile country as soon as navigation, nursed in the Mediterranean, had advanced sufficiently to embrace the whole ocean-coasts of Asia, Africa, and America. But without coal and iron we should have been mere merchants, not manufacturers. London, Liverpool, Glasgow, and Southampton might possibly have been not inconsiderable marts for exchanging the products of other countries, and for balancing the trade in raw cotton or sugar from India and America against the textile fabrics and the hardware of France and Belgium. But we should have had no Birmingham, no Manchester, no Sheffield, no Leeds, no Bradford, no Paisley, no Belfast. Our population would not have reached one half its present size. Lancashire, the West Riding of Yorkshire, and the busy mining district of South Wales would be as thinly inhabited as Merionethshire and Connemara. The Black Country would be a quiet pastoral and agricultural region like the remainder of Warwick and Stafford. We should have no great towns except on the seaboard and the navigable rivers, and even these would only attain a fraction of their existing dimensions. Most of our people would be engaged in farming, and there would be no great wealthy class to crowd into Brighton, Scarborough, Cheltenham, Torquay, and the Scottish Highlands.
But this is not all: the difference in our national character would no doubt be very great. Coal has stimulated our inventive faculties and our enterprise, and has given an indirect impetus to science and art. Without it we should have had fewer mechanical improvements, fewer scientific discoveries, fewer railways, fewer colleges and schools. All these things have reacted upon our general level of intelligence and taste, and have enabled us to hold our own among the most advanced European nations. But without coal and iron we should have fallen back to somewhat the same position as that now held by Holland or Scandinavia, allowance being made for a larger territory in the first case, and a thicker population in the second. Our comparatively insignificant numbers would reduce us from the rank of a first-class European power to that of a nation existing on sufferance. Our army and navy would be smaller; our Parliament less important and less stimulating to high ambitions; our churches, our bar, our medical faculty less advanced in the fore-front of thought. Thus we should probably suffer in every respect, producing both absolutely and relatively fewer great men, either as thinkers, administrators, discoverers, inventors, or artists. For, when once a nation has fallen behind in the race, the audience addressed becomes smaller, the competition less keen as an incentive to effort, the rewards of success decrease in value, and the general atmosphere of example and rivalry deteriorates in power. Where few books are written, few investigations undertaken, few works of art produced, few and still fewer care to aspire toward a forgotten ideal. Thus, without coal, Britain might have declined from the England of Shakespeare, Milton, and Newton, just as other countries have ^declined from the Hellas of Pericles and Plato, and the Spain of Cervantes and Velasquez.
The relation between physical conditions and history in its wider acceptation being thus fundamental, it may be well to consider in somewhat greater detail the special reactions of a single tolerably definite portion of the natural environment upon human development. For this purpose we may choose the science of geology. It might seem at first sight that geological facts had very little to do with the course of history. Rocks and clays, lying often far beneath the surface, and comparatively disregarded till a late stage of civilization, would appear far less important in the evolution of mankind than plants and animals, geographical situation and meteorological conditions. But, though doubtless of inferior practical interest to these superficial phenomena, the geological constitution of the soil is yet pregnant with innumerable reactions upon the life of human beings who dwell upon its surface. I hope to show in the sequel that the rocks or minerals which lie beneath the thin coating of earth and vegetation have always exerted an immense though often unsuspected influence upon the history of man. And I shall choose most of my examples from well-known facts of the British Isles, only diverging elsewhere very occasionally for the sake of more striking or more conclusive instances.
To begin with, it must be premised that geological conditions were of comparatively less importance in very primitive times, and have increased in their practical relation to humanity with every additional step in general culture. This is only what we must expect from the nature of the case. Man's connection with his environment has necessarily grown more and more complex as his evolution proceeded. Soil becomes a matter of interest sooner than building-stone; potter's clay precedes copper or iron ore as a valuable object; metals of every kind are earlier required than coal. The mere savage needs nothing more from the mineral world than flint for his arrow-head and ochre for his personal adornment. A little later he requires bronze for his hatchet, gold and amber for his rude jewelry, clay for his hand-molded earthenware. A still more advanced race will learn to prize silver for coins, lapis lazuli for gems, brick-earth for Assyrian temples, granite for Egyptian colossi, marble for Hellenic sculpture, and iron for Roman swords. Only at a very late period of development will man begin to be largely affected by the neighborhood of zinc, lead, and mercury, of rock-salt, kaolin, and plumbago, of slate-quarries, marl-pits, and pipe clay beds. Last of all will come the economic employment of coal, which in our own island has caused the aggregation of densely massed populations around the great centers of Glasgow, Manchester, Leeds, Sheffield. Newcastle, and Birmingham.
How general is the relation in early stages of civilization we can see from the comparatively close similarity between the life and arts of all the lowest savages. How special it becomes in advanced societies we can see when we consider the cases of Bethesda growing up by the side of the Penrhyn slate-quarries; of Broseley, entirely engaged in the manufacture of clay tobacco-pipes; and of Northwich, Middlewich, and Nantwich supporting themselves by mining rock-salt.
Nevertheless, even at the earliest period, geological conditions must have largely influenced human life. Tribes which lived among rugged granite or limestone mountains must have been very differently circumstanced from those which ranged over level tertiary lowlands, or settled on the alluvial deltas of modern rivers. During that primitive epoch which Sir John Lubbock has christened the Palæolithic age, when man first dwelt in Britain, we see traces of such primeval differentiation. The naked or skin-clad savages, who then hid among the caves of southeastern England, were ignorant of all the metals, as well as of pottery, and only employed rudely chipped weapons of unground flint. The neighboring forests then contained the mammoth and the woolly rhinoceros, the urus and the musk-ox, while the hippopotamus still basked on the banks of the Ouse and the Thames. But man appears at that period to have been wholly confined to the southeastern corner of England, from the coast of Devonshire to that of Lincoln. This district roughly coincides with that in which he could obtain flints for the manufacture of his weapons; and it also comprises the most level portion of Britain, where he might find comparative security and well-stocked hunting-grounds among the low-lying jungles of the eastern counties, the Thames Valley, and the tertiary plains of Hampshire. He does not seem at this early age to have ventured among the wild primary hills of Cornwall, Wales, the Pennine chain, and the Scottish Highlands, but rather to have clung about the river fisheries and the flat shores of the southeast. Perhaps the bare and treeless chalk downs whicH run from Beer in Devonshire to the Norfolk coast, backed by a forest-belt on the oölite in the rear, may have checked his westward advance through the fear of meeting the cave-lions and other savage wild beasts of the preglacial period on the open plain.
At a far later date, when man had progressed from the hunting to the pastoral stage, and had learned to fashion weapons of polished stone or bronze, which made him the acknowledged master of the brute creation, it is clear that a great change must have taken place as regards the relation to geological conditions. And in Britain the men of this later period certainly spread over the whole country, gathering most thickly, it would seem, where pasturage was easiest for their herds and flocks. This would naturally be upon those same undulating chalk downs which were doubtless objects of terror to the earlier race. Hence we find the tumuli and other memorials of the Euskarian and Keltic inhabitants—belonging either to the neolithic, the bronze, or the iron age—most thickly clustered around the great monument of Stonehenge on Salisbury Plain, among the downs about Brighton or Lewes, and on the sides or summits of the Yorkshire and Lincolnshire wolds. In those days and for many centuries after, the Weald of Kent lay as a wild forest-belt between the open chalk country to the north and south; while the primary hills and the river valleys still consisted for the most part of unbroken underbrush and woodland. Even in these early times, however, a commerce based upon geological differences had already sprung up: for the beautiful jade, employed as material for the finest hatchets, has been recognized as coming from the Kuen-Lun Mountains of Central Asia, while amber was already imported from the banks of the Baltic. Within Britain itself the Cornish tin-mines probably supplied the metal which mingled with copper to form the bronze implements of all Western Europe. An industrial population must even then have gathered with comparatively considerable density above the ores of the Land's End, while the valley of the Thames remained a mere desolate jungle wandered over by a few stray families of savage hunters.
Agriculture must first have developed itself over the whole world on low alluvial ground. Hence we find that all the great early civilizations occupy river valleys—such as those of the Nile, the Euphrates, the Ganges, the Indus, and the Hoang-Ho. Here alone can large masses of men obtain subsistence, before navigation and scientific agriculture have reached a considerable stage of evolution. Here, too, the density of the population and the level nature of the soil permit the growth of those vast despotisms under which alone an early society can be organized with any high degree of internal diversity. But just as navigation, nursed on inland and island-studded seas, spreads afterward to the wider oceans, so agriculture, nursed on well watered alluvial plains, spreads afterward to drier, rockier, or more mountainous districts. In the desert uplands of the Punjaub, cultivation exists wherever wells can be sunk, even at immense depths, and the industrious Jat peasantry work ceaselessly day and night by relays, each family raising the precious water to fertilize its own little plot, for a stated number of hours out of the twenty-four. But such industry presupposes a long training in more fertile soils, and a heavy pressure of population on all the earlier occupied alluvial lowlands. So too in Britain, a primitive agriculture would have despaired of raising corn upon the bare sides of the Chiltern Hills, and only modern scientific farming has turned the boggy upland expanses of the Cheviots and Lammermoor into nourishing tillage. Accordingly, we might expect that the growth of agriculture would bring geology and human development into still closer connection within our island.
Geologically, Britain falls into two well-marked divisions—the northwestern primary tract, and the southeastern secondary and tertiary region. The boundary between them may be roughly marked off by a line running from the mouth of the Tees to the mouth of the Exe. Northwestward of this line we have the whole of Scotland, the Pennine region of England, the Welsh mountain system, and the peninsula of Devonshire and Cornwall. Southeastward we have the whole level country of England, comprising the plain of York, the great central plateau, the Fen district and the eastern counties, the valley of the Thames, and the watershed of the south coast.
Now, it is not too much to say, that by far the most fundamental fact in the annals of Britain, since the dawn of written history, is the great revolution which has exactly reversed the relative importance of these two divisions. Yet what are called histories of England at the present day utterly ignore that revolution. In the Roman period and the middle ages, the most valuable and most populous part of Britain was the secondary and tertiary lowland: at the present day, the most valuable and most populous part is the primary division to the north and west. And what gives this revolution its greatest ethnological interest is the fact that while the secondary tract roughly corresponds with the Teutonic portion of Britain, the primary tract roughly corresponds with the Keltic or semi-Keltic portion.
As early as the time when Caius Cæsar, the Dictator, landed in our island, these two great divisions had already shown their differentiating characteristics. The Britons of the southeastern country, consisting of open and easily cultivable plains, had advanced to the agricultural stage, and were comparatively dense in their pressure upon soil, with fixed habitations and considerable towns. The northwestern tribes were still pastoral nomads or hunters, dwelling in movable villages, and having mere empty forts on the hill-tops, to which the whole population retreated in case of invasion. The difference thus expressed continued more or less marked throughout the whole historical period, until the use of coal effected that extraordinary revolution by which primary and industrial Britain has at length asserted its superiority to the level agricultural southeast.
Under the Romans Britain became a corn-producing and grain exporting agricultural country, like the America of our own day. And just as the valley of the St. Lawrence and the northern Mississippi basin now form the most important wheat-growing part of America, so the valleys of the greater rivers formed the most important part of Roman Britain. The plain of York, formed by the Ouse and other tributaries of the Humber, is the largest low-lying corn-field and meadow-land in our country. It consists mainly of triassic strata, overlaid in the lower reaches by a deep bed of alluvium. In the center of this rich agricultural tract lay the Roman provincial capital of Eboracum. Another wealthy region is the post-tertiary level of the eastern counties; and here the colony of Camalodunum lay surrounded by numerous villas of rich land-owners. The tertiary valley of the Thames shows its importance by including the considerable cities of Londinium, Verulamium, and Rhutupite. Other Roman towns—Lincoln, Cirencester, Bath, and Dorchester—filled up the rich oölitic and green-sand belt of central England; while Winchester overlooked the tertiary vale of the Itchin at Southampton, and took its name of Venta Belgarum from the-agricultural lowland at its doors. We may gather from the Roman historians that the occupation of southeastern Britain was real and thorough. The native population was reduced to serfdom, and the country became a mere feeder of Rome or of the Gallic cities.
Primary Britain, however, seems never to have fallen into so miserable a condition. The Roman supremacy was here probably confined to a mere military occupation, like our own occupation of Kumaon or the Simla Hills. Caledonia never fell into their hands, and even in Wales and the Pennine chain we find only military stations, like Isca Silurum or Segontium, not large cities like London, York, and Lincoln. Even where the Romans thoroughly penetrated the primary region, as in Cornwall or the Forest of Dean, it was always for a geological reason, to secure the mines of tin or iron. This difference, I believe, had almost as much to do as geographical position with the subsequent relations of the Britons to the English invaders. While the servile herd of the Belgian, Icenian, Trinobantian, and Brigantian country, demoralized by Roman centralization, fell easily before the Jutish or Anglian pirates, the more independent mountaineers of Wales, Cumbria, and Strathclyde long resisted the English onslaught, and only at last succumbed as free subject races, instead of being enslaved or exterminated like their eastern fellow countrymen. The Scottish Highlands not only retained their own independence, but even gave their kings to the Teutonic Lothians. Granite naturally makes freemen, as alluvium naturally makes slaves.
When the English settled in southeastern Britain, they occupied for the most part the secondary and tertiary plain. But they also pushed northward into the primary region up to the Firth of Forth, as the Romans had done before them. The Teutonic invaders, in other words, took the best agricultural lands for themselves, while the Kelts were driven back into the rugged primary tract of hill and forest. Throughout the middle ages, agriculture and grazing formed the staple English industries. Accordingly, during the early English period, we find all the more important towns occupying the cultivable valleys or gentle plains. Canterbury and Rochester, the two Kentish capitals, stand in the midst of tertiary lowlands; London, the final royal city of the West Saxon kingdom, lies surrounded by a similar tract; the Oxfordshire Dorchester, first home of the Wessex kings, is on the border of the rich vales of Aylesbury and Oxford; Winchester, their later seat, commands the valleys of the Itchin and the Test. Norwich, Bury St. Edmunds, and Ipswich were important centers for the East Anglian drift. Peterborough and Ely rose among the levels of the Nen and the fens of the Ouse. Lincoln, Oxford, and Chippenham stood upon the great central oölitic belt. Cambridge occupied a low-lying corner of the cretaceous system. Exeter, Lichfield, and Chester were girt round with the fertile triassic meadow-lands. York still remained the capital of the north, and the metropolis of a kingdom which long retained the foremost position held by the north under Roman rule. These were the great cities of England before the Norman Conquest, and not one of them stands upon a primary formation. All of them, save only London, have now sunk to the position of mere cathedral cities, university towns, or agricultural centers. But Edinburgh, Glasgow, Manchester, Leeds, Sheffield, Newcastle, Bristol, and Cardiff, the great cities of to-day, are all built upon primary rocks; while the only two important modern towns which rest on later strata are Birmingham, on the borders of the Black Country coal-field, and Liverpool, which lives by conveying the cotton of America to the great Lancashire colliery district around Manchester, Rochdale, and Oldham.
In the later middle ages England became a wool-stapling country. Bales of wool were shipped from the Orwell for Flanders and Italy, as they are now shipped from Australia for Leeds and Bradford. This was the first step toward making Britain a commercial country. Before the Norman Conquest it had been an essentially agricultural and self-sufficing community, growing all that it required to meet its own simple needs, and neither exporting nor importing goods to any noticeable extent. But the wool export created a foreign trade. Ports sprang up along the south and east coasts, from Dartmouth, Topsham, and Lyme Regis to the now forgotten haven of Ravenspuron-Humber, the precursor of our modern Hull. This trade gave importance to the chalk districts, high sheep-walks now the barest and least inhabited portion of southeastern England. Not a single town of any pretensions at present occurs in any part of the downs or wolds. But Dorchester, Shaftesbury, Old and New Sarum, Winchester, Lewes, Reading, Wallingford, Cambridge, and Beverley, were all places of great mediæval importance, and all stand within the cretaceous area. Other wool-growing tracts of course possessed a similar value.
A few more special agricultural features of the various secondary or tertiary geological formations may here he fitly introduced. The Trias and other "Poikilitic" strata, running across England from the Tyne to the Exe, form beautiful undulating country, comprising much of the best wheat-growing and pasture land, and famous for the production of cheese. In this belt lie the vale of York, the Trent and Severn Valleys, the Cheshire Plain, and the vales of Exeter and Taunton. An outlier forms the valley of the Eden at Carlisle. The Lias, which follows the Poikilitic series to the southeast, is a good soil for corn and apples, but also produces the most excellent cheese in England, as Mr. Woodward has pointed out. Along the Severn bank it furnishes the double Gloucester; at Melton Mowbray and Leicester it produces Stilton; and in Somersetshire it unites with the triassic red marl to yield the Cheddar. The fruitful vales of Eversham and Gloucester belong to this formation. The Oölite gives us the rock known as cornbrash, which disintegrates into a splendid wheat-bearing soil, naturally manured by its large quantities of phosphate of lime, the so-called bone-earth. The Oxford Clay, on the other hand, is poor and hard to cultivate, so that most of it lies under permanent pasture. It forms the sheep-feeding vale of Blackmore, in Dorset. The Kimmeridge Clay, in like manner, does not repay cultivation, and is mostly employed for meadow or woodland. The Wealden, forming the great trough between the North and South Downs, is another of the infertile soils. It remained a great wood, the Andredesweald, or Forest of Anderida, for a long period after the English conquest, and the local names of the district still retain their forestine terminations of hurst, ley, den, or field. Even at the present day the Weald is damp and clayey land, little tilled, and either laid down in pasture or given over to furze and heath. The Gault makes good grazing-lands, and the Upper Greensand is in every respect a fertile formation. These two series yield the rich Vale of White Horse, through which the Great Western Railway runs between Swindon and Didcot, as well as the vale of Aylesbury, whose name has become synonymous with pure milk. The Chalk supplies us with South Down mutton, said to owe its excellence not so much to the pasture itself as to a small land-snail (Helix virgata) which the sheep devour in great numbers. The London clay, though stiff, can be made to yield good crops. Drift forms the great East Anglian plain, while the Fen country, the Somersetshire levels, and Holderness consist mainly of alluvium. Thus we see that, little as the mediæval farmer suspected it, the distribution of his corn-fields and pasture-lands, his orchards and sheep-walks, nay, even of the royal forests and the barren heaths, was finally dependent upon underlying geological conditions.
Even in mediæval and agricultural England, however, certain particular spots acquired a special industrial character from the nature of the subjacent strata. The occurrence of fuller's earth in the Stroud Valley and near Bath and Bradford gave rise to the west country cloth-trade. Salt was pumped from several inland wells in the Trias at Droitwich in Worcestershire, at Northwich, Sandbach, Middlewich, and Nantwich in Cheshire, and at Shirleywich in Staffordshire. The bays in which sea-water had been evaporated to yield salt had been known as "wyches," and the same word was applied to the new wychhouses of the interior. Clay suitable for potteries was found in many places, and naturally produced a small trade. But mines were little worked, and building-stone, of which more must be said hereafter, formed almost the only other geological differentiating factor between various districts.
The change to the modern industrial distribution is far too large a subject to be treated otherwise than quite cursorily here; but a few traits of the change may perhaps be sketched with a rapid pen. In Britain mineral wealth is almost universally connected with the primary formations. Our coal more especially has formed the great central pivot upon which turns the whole manufacturing and commercial system of the country. As soon, therefore, as the use of steam began to revolutionize our industrial world, the primary tracts of England, Wales, and Scotland, rose to the highest importance. The population of Britain suddenly found itself turned back upon the Keltic and coal-bearing regions. A slight classification of the various great towns of modern Britain according to the coal-fields in which they stand, or on which they depend, will serve to show the vastness of the revolution.
In or around the Scottish coal-field stand Glasgow, Paisley, and Greenock. Above the Tyne colliery region are Newcastle, North Shields, and Durham, while close at hand lie Sunderland, Stockton, Darlington, Middlesborough, and the Cleveland iron district. The Lancashire field incloses Manchester, Blackburn, Wigan, Bolton, St. Helens, Burnley, Middleton, Oldham, Rochdale, and Ashton, with Liverpool for its port, and Preston and Macclesfield upon its outskirts. An outlier contains Stoke-upon-Trent and Newcastle-under-Lyne. The West Riding coal-field includes Leeds, Bradford, Wakefield, Barnsley, Sheffield, and Chesterfield, while Huddersfield, Nottingham, and Derby hang upon its border, and Hull supplies it with an eastward outlet. The Staffordshire tract comprises Wolverhampton, Bilston, Dudley, Wednesbury, and Walsall, with Birmingham for its real center. Other carboniferous deposits occur in Coalbrookdale, in the crowded South Wales district, and near Bristol. If all these are put together, it will be seen that they compose almost all the great foci of British life and manufactures at the present day.
On the other hand, what are the great towns in the secondary and tertiary southeastern tract? London, the main distributing center, preserved by its navigable river, and its official importance. Southampton, a convenient Indian and South American port. Plymouth and Portsmouth, two government naval stations. Chatham, an artificial creation for purposes of war. Scarborough, Brighton, Cheltenham, Bath, and half a dozen other lounges for the moneyed classes. All these ultimately depend for existence upon the wealth created elsewhere. Leicester is almost the only town in purely Teutonic England which now earns a good livelihood by industries unconnected with the sea or with warlike preparations. Turning to the north, Edinburgh survives by its traditional position as a metropolis and as the center of the Scottish Church, the Scottish law, and to some extent the Scottish aristocracy, as well as by its possession of a university and a great cultivated society. But Edinburgh itself stands on a primary site.
The specialties of the modern system are far too numerous to allow even of passing exemplification. Here coal, there iron, in other places lead or tin, forms the source of wealth and the determining cause of human aggregation. The potteries draw men to Staffordshire; finer clays produce the ware of Worcester, Lambeth, or Dunmore. Flags for paving are largely worked in North Wales. Lime from blue lias keeps alive more than one small seacoast town. Even gold is mined near Dolgelley in Merionethshire. Phosphate of lime is collected as mineral manure. Cutler's green-stone and beds of jasper are found among the Cambrian rocks. Millstones, hearthstones, and fire-clay are other useful economic products. Terra-cotta is made at Watcombe, near Torquay. Epsom salts are manufactured from magnesian limestone on the Tyne. Slates for roofing, plumbago, Cairngorm pebbles, afford occupation in other parts to quarrymen and lapidaries. Glass can only be made where flints are obtainable. Whitby derives a small fortune from alum, jet, and the sale of fossils. Guernsey lives largely by exporting its granite as road metal to London. Whetstones supply an industry to Whittle Hill, and slate-pencils to Shap in Cumberland. But perhaps the strangest trade of all is that of the gun-flints, still manufactured at Brandon and Norwich to supply the savages of Africa, whither all the old flint-locks of Europe were shipped on the invention of percussion caps. The water-supply everywhere depends upon geological conditions. Even our pleasure resorts and watering-places owe their attractions to similar considerations, as we can see when we examine the igneous masses of the Scotch Highlands, which form the chief heights of the Grampians; or when we remember that the self-same Cambrian rocks recur in the loveliest part of North Wales and in the Westmoreland lake district. So too in Devonshire, the regular tourist tract from Ilfracombe to Lynton and Lynmouth lies through the wild Devonian strata, which, interspersed with granite, once more reappear on the other tourist coast-line from Torquay to Land's End. Those who admire Ramsgate and Margate, with their bare, treeless downs and white chalk-cliffs, may also content themselves with the similar scenery of Dover, Folkstone, Eastbourne, or Brighton; but a different type of mind will prefer the wooded vales of Hastings, where the Weald comes down with its pleasant broken country to the seashore.
One last word may be given to the influence of geology upon art. We can hardly deny that the whole æsthetic development of Egypt must have been largely affected by its alternation between solid granite and the mud of the Nile. So, too, the Parthenon and the Apollo must have owed much to the marble of Paros and Pentelicus. China has doubtless been greatly influenced by the presence of kaolin clay. In Assyria, brick necessarily formed the chief building material; and in Upper India the monasteries and stupas of the Buddhist Emperor Asoka are still recognized by their huge, sun-dried bricks. Chryselephantine art could never alone produce high results; marble and alabaster would naturally yield far more elevated works. In Britain we may look for similar effects of the geological environment.
As early as the age when Stonehenge was piled up, building-stone was selected for special purposes, since the outer circle of that prehistoric monument consists of the Sarcen bowlders of the neighboring plain; but the inner pillars are of diabase, and have been brought from some unknown distance. During the middle ages Caen stone was frequently imported for building churches or other important architectural works. Before the Norman Conquest, however, most English buildings were of wood, so that, "to timber a minster," not to build a church, is the good early English expression of the chronicle. In chalk districts, at a later date, broken flints were often employed, and they give a mean appearance to the abbey ruins and churches at Reading, as well as to most of the older edifices at Brighton. Oxford, however, on the Oölite, is happily built of good native or imported stone. In modern times, London, standing in the midst of the brick-earth, has fallen a victim to the miseries of stucco, until the Queen Anne revivalists have endeavored to restore an honest red brick; whereas Edinburgh, surrounded by excellent building-stone, has been able to do justice to its magnificent natural situation, and Aberdeen has clad itself in the stern but not unattractive gray and blue of its own solid granite. To the Caen stone, the Bath stone, and the Portland stone we owe half our cathedrals and abbeys, whose delicate tracery could never have been wrought in Rowley rag or Whin Sill basalt. The architecture of granite or hard limestone regions is often massive and imposing, but it always lacks the beauty of detailed sculpture or intricate handicraft. The marble lattice-work of the Táj or the "prentice's pillar" of Roslyn Chapel is only possible in a soft and pliable material.
Thus we see that agriculture and manufactures, art and science, are all largely influenced by geological conditions. Indeed, it would not be too much to assert that, after climate and geographical situation, geology is the greatest differentiating agent of national character. Every people is primarily what it is in virtue of the heredity it derives from the common ancestors of its whole stock; but, so far as it differs from other descendants of the same stock, the differences must mainly have been caused by those three great natural agencies, acting and reacting in conjunction with the original hereditary tendencies. The immense complexity of such actions and reactions renders them difficult to trace in detail; but the general principle which they illustrate can hardly be missed by those who read history with a wide and comprehensive glance.—Fraser's Magazine.
- These little mollusks themselves abound upon chalky soils, and are found nowhere else, because they require large quantities of calcareous matter to form their banded shells, while other species with more horny coverings live on soils where less lime can be obtained. No snails can inhabit the limeless district of the Lizard in Cornwall. So minute are the interpendences between every portion of organic and inorganic nature.
- I owe this, with many other facts, to Mr. H. B. Woodward's interesting "Geology of England and Wales."
- Parker's cement, manufactured from the septaria of the London clay, is answerable for the outer coating of our West-end houses.