Note F, p. 26.
In this section, Cuvier gives a clear and distinct account of several kinds of alluvial formations. M. De Luc, in the first volume of his Geological Travels, describes the alluvial formations that cover and bound many of the islands in the Baltic, and upon the coast of Denmark, and gives so interesting an account of the modes followed by the inhabitants, in preserving these alluvial deposites, that we feel pleasure in communicating it to our readers.
“During my stay at Husum, I had the advantage of passing my evenings very agreeably and profitably at the house of M. Hartz, with his own family, and two Danish officers, Major Behmann, commandant at Husum, and Captain Baron de Barackow. The conversation often turned on the objects of my excursions, and particularly on the natural history of the coasts and of the islands; respecting which, M. Hartz obligingly undertook to give me extracts from the chronicles of the country. This led us to speak of the Danish islands; and those officers giving me such descriptions of them, as were very interesting to my object, I begged their permission to write down, in their presence, the principal circumstances which they communicated to me. These will form the first addition to my own observations; I shall afterwards proceed to the information which I obtained from M. Hartz.
The two principal islands of the Danish Archipelago, those of Funen and Seeland (or Zeeland), as well as some small islands in the Kattegate, namely, Lenoe, Anholt, and Samsoe, are hilly, and principally composed of geest[379]; and in these are found gravel and blocks of granite, and of other stones of that class, exactly in the same manner as in the country which I have lately described, and its islands in the North Sea. On the borders of the two first of these Danish islands, there are also blocks in the sea; but only in front of abrupt coasts, as is the case with the islands of Poel and Rugen, and along the coasts of the Baltic. The lands added to these islands of geest are in most part composed of the sand of the sea, the land-waters there being very inconsiderable; and to the south of them have been formed several islands of the same nature, the chief of which are Laland and Falster, near Seeland. These, like the marsh islands in the North Sea, are sand-banks accumulated by the waves, and, when covered with grass, continuing to be farther raised by the sediments deposited between its blades. In the Baltic, where there are no sensible tides, such islands may be inhabited without dikes, as well as the extensions of the coasts; because, being raised to the highest level of that sea, while their declivity under water is very small, and being also more firm in their composition, the waves die away on their shores; and if, in any extraordinary case, the sea rises over them, it leaves on them fresh deposits, which increase their heights. These soils are all perfectly horizontal, like those added to the coasts of the Continent.
Some of these islands approach entirely, or in part, to the nature of that of Rugen. This island of Seeland, on that side which is called Hedding, has a promontory composed of strata of chalk with its flints. The island of Moen (or Mona), on the south of the latter, has a similar promontory near Maglebye and Mandemark; and the island of Bornholm, the easternmost of those belonging to Denmark, contains strata of coal, covered by others of sandstone. Phenomena like these, evident symptoms of the most violent catastrophes at the bottom of the ancient sea, proceeding, as I think I have clearly shewn, from the subsidence and angular motions of large masses of strata, which must have forced out the interior fluids with the utmost impetuosity, it is not surprising that so many fragments of the lowermost strata are found dispersed over this great theatre of ruins.
I now proceed to the details which I received from M. Hartz; beginning by a specific designation of the islands dependent on the province of Sleswigh, such as they are at present, belonging to the three classes already defined. To commence from the north; Fanoe, Rom, Sylt, and Amrom, were originally islands of the same nature as the neighbouring continent, but have been since extended by marsches[380]. The soil of these islands, with its gravel and blocks of primordial stones, was at first barren, as the geest is naturally every where; but is become fertile by manure, of which there has been no deficiency, since those grounds have been surrounded with marsch, where the cattle are kept in stables during the winter. In the island of Sylt, there are spaces consisting of moor, but its head of land, which extends on the south as far as Mornum, is composed entirely of marsch, and is bordered with dunes towards the open sea, because, the sediments of the rivers not reaching any farther, the sea-sand impelled against it by the waves remains pure, and is thus raised by the winds in hillocks on the shore. The shallow bottom of the sea, between this island and that of Fora, is of geest: at low water, it may be passed over on foot; and there are found on it gravel and blocks of granite. But on the same side of Fora there is a great extent of marsch, beginning from St Laurencius. Among the islands consisting entirely of marsch and surrounded with dikes, the most considerable are Pellworm and Nord Strand; and among the Halligs, or those inhabited without dikes, the chief are Olant, Nord-marsh, Langne, Groode, and Hooge.
Such are the islands on this coast, in their present state, now rendered permanent by the degree of perfection at which the art of dike-making is arrived. But, in former times, though the original land was never attacked by the sea, which, by adding to it new lands, soon formed a barrier against its own encroachments, the latter, and the islands composed of the same materials, were subject to great and sudden changes, very fatal to those who were engaged to settle on them by the richness of their soil, comparatively with the continental. The inhabitants, who continued to multiply on them during several generations, were taught, indeed, by experience, that they might at last be invaded by the element which was incessantly threatening them; but having as yet no knowledge of natural causes, they blindly considered those that endangered them as supernatural, and for a long time used no precautions for their own security. They were ignorant of the dreadful effects of a certain association of circumstances, rare indeed, but, when occurring, absolutely destructive of these marsches. This association consists of an extraordinary elevation of the level of the North Sea, from the long continuance of certain winds in the Atlantic, with a violent storm occurring during the tides of the new or full moon; for then the sea rises above the level of all the marsches; and before they were secured against such attacks, the waves rolling over them, and tearing away the grass which had bound their surface, they were reduced to the state of mere banks of sand and mud, whence they had been drawn, by the long course of ordinary causes. Such were the dreadful accidents to which the first settlers on these lands were exposed; but no sooner were they over, than ordinary causes began again to act; the sand-banks rose; their surface was covered with grass; the coast was thus extended, and new islands were formed; time effaced the impression of past misfortunes; and those among the inhabitants of these dangerous soils, who had been able to save themselves on the coast, ventured to return to settle on them again, and had time to multiply, before the recurrence of the same catastrophes.
This has been the general course of events on all the coasts of the North Sea, and particularly on those of the countries of Sleswigh and Holstein. It is thus that the origin and progress of the art of dikes will supply us with a very interesting chronometer in the history of the continent and of man, particularly exemplified in this part of the globe. A Lutheran clergyman, settled in the island of Nord Strand, having collected all the particulars of this history which the documents of the country could afford, published it in 1668, in a German work, entitled The North Frisian Chronicle. It was chiefly from this work, and from the Chronicle of Dankwerth, that M. Hartz extracted the information which he gave to me, accompanied by two maps, copied for me, by one of his sons, from those of Johannes Mayerus, a mathematician; they bear the title of Frisia Cimbrica; one of them respecting the state of the islands and of the coast, in 1240, as it may be traced in the chronicles, and the other, as it was in 1651.
According to these documents, the first inhabitants of the marsches were Frisii or Frisians, designated also under the names of Cimbri and Sicambri: the latter name, M. Hartz conjectures, might come from the ancient German words Seekampfers, i. e. Sea-warriors; the Frisians being very warlike. These people appear to have had the same origin with those, who, at a rather earlier period, took possession of the marsches of Ost-Frise (East-Friesland), and of that Friesland which forms one of the United Provinces; but this common origin is very obscure. Even at the present day, the inhabitants of the marsches, from near Husum to Tondern, or Tunder to the North, though themselves unacquainted with it, speak a language which the other inhabitants of the country do not understand, and which is supposed to be Frisian. It is the same at a village in the peninsula of Bremen, by which I have had occasion to pass.
The Sicambri or North Frisians, are traced back to some centuries before the Christian era. At the commencement of that era, they were attacked by Frotho, King of Denmark, and lost a battle, under their king Vicho, near the river Hever. Four centuries afterwards they joined the troops of Hengist and Horsa. In the year 692, their king Radebot resided in the island of Heiligeland. Charles Martel subdued them in 732; and some time afterwards they joined Charlemagne against Gottric, King of Denmark. These are some of the circumstances of the history of this Frisian colony, recorded in the chronicles of which I have spoken; but the history here interesting to us is that of the lands whereon they settled.
It appears that these people did not arrive here in one body, but successively, in the course of many years: they spread themselves over various parts of the coasts of the North Sea, and even a considerable way up the borders of the Weser and the Elbe; according to documents which I have mentioned in my Lettres sur l’Histoire de la Terre et de l’Homme. These new settlers found large marsches, formed, as well in the wide mouths of those rivers as along the coasts, and around the original islands of geest; especially that of Heiligeland, the most distant from the coast, and opposite the mouth of the Eyder. Of this island, which is steep towards the south, the original mass consists of strata of sandstone; and at that time its marsch extended almost to Eyderstede: there were marsches likewise around all the other original islands; besides very large islands of pure marsch in the intervals of the former.
All these lands were desert at the arrival of the Frisians; and the parts on which they established their first habitations, to take care of their breeds of horses and cattle feeding on the marsches, were the original eminences of the islands; on that of Heiligeland they built a temple to their great goddess Phoseta, or Fosta. When they became too numerous to confine themselves to the heights, their herds being also greatly multiplied, they ventured to begin inhabiting the marsches; but afterwards, some great inundations having shewn them the dangers of that situation, they adopted the practice followed by those who had settled on the marsches of the province of Groningen, and still continued on the Halligs; that of raising artificial mounts called werfs, on which they built their houses, and whither they could, upon occasion, withdraw their herds; and it likewise appears, that, in the winter, they assembled in greater numbers on the spots originally the highest, in the islands, as well as on some parts of the coasts.
Things continued in this state for several centuries; during which period, it is probable that the inhabitants of these lands were often, by various catastrophes, disturbed in the enjoyment of them, though not discouraged. But in 516, by which time these people were become very numerous, more than 600 of them perished by one of the concurrences of fatal circumstances already defined. It was then that they undertook the astonishing enterprise of enclosing these lands. They dug ditches around all the marsches, heaping up on their exterior edge the earth which was taken out; and thus they opposed to the sea, dikes of eight feet in height. After this, comprehending that nothing could contribute more to the safety of their dwellings, than to remove the sea to a greater distance, they undertook, with that view, to exclude it from the intervals between the islands, by uniting, as far as should be possible, those islands with each other. I will describe the process by which they effected this, after I shall have recalled to attention some circumstances leading to it.
From all that I have already said of the fore-lands, and of the manner in which they are increased, it may be understood, that the common effects of the waves and of the tides is to bring materials from the bottom of the sea towards the coasts; and that the process continues in every state of the sea. The land winds produce no waves on the coasts, which can carry back to the bottom of the sea what has been brought thence by the winds blowing against the shore; and as for the tides, it may have been already comprehended (and shall soon be proved), that the ebb carries back but very little of what has been brought by the flood. So that, but for some extraordinary circumstances, the materials continually impelled towards the shore, which first form islands, would at last unite against the coast in a continuous soil. The rare events, productive of great catastrophes, do not carry back these materials towards the bottom of the sea; they only, as it has been said before, ravage the surface, diminishing the heights, and destroying the effect of vegetation. These, then, were the effects against which it was necessary to guard.
I now come to the plan of uniting the islands, formed by these early inhabitants. They availed themselves for that purpose of all such parts of the sand-banks as lay in the intervals between the large islands, and were beginning to produce grass. These, when surrounded with dikes, are what are called Hoogs; and their effects are to break the waves, thus diminishing their action against the dikes of the large islands, and, at the same time, to determine the accumulation of the mud in the intervals between those islands. In this manner a large marsch island, named Everschop, was already, in 987, united to Eyderstede by the point on which Poppenbull is situated; and in 995, the union of the same marsches was effected by another point, namely, that of Tetenbull. Lastly, in the year 1000, Eyderstede received a new increase by the course of the Hever, prolonged between the sand banks, being fixed by a dike; but the whole still remained an island. This is an example of the manner in which the marsch islands were united by the hoogs; and the chronicle of the country says, that, by these labours, the islands were so considerably enlarged in size, and the intervals between them so much raised, that, at low water, it was possible to pass on foot from one to the other. The extent of these marsches was so great on the coast of Sleswigh alone, that they were divided into three provinces, two of which comprehended the islands, and the third comprised the marsches contiguous to the coast; and the same works were carried on upon the marsches of the coast of Holstein.
But the grounds thus gained from the sand-banks were very insecure; these people, though they had inhabited them more than ten centuries, had not yet understood the possibility of that combination of fatal circumstances above described, against which their dikes formed but a very feeble rampart; the North Sea, by the extraordinary elevations of its level, being much more formidable in this respect than the ocean, where the changes of absolute level are much less considerable. I shall give an abridged account of the particulars extracted by M. Hartz from the chronicle of Dankwerth, relative to the great catastrophes which these marsches successively underwent, previously to the time when experience led to the means necessary for their security.
In 1075, the island of Nord Strand, then contiguous to the coast, particularly experienced the effect of that unusual combination of destructive causes; the sea passing over its dike, and forming within it large excavations like lakes. In 1114 and 1158, considerable parts of Eyderstede were carried away; and in 1204, the part called Sudhever in the marsch of Uthholm was destroyed. All these catastrophes were fatal to many of the marsch settlers; but in 1216, the sea having risen so high that its waves passed over Nord Strand, Eyderstede, and Ditmarsch, near 10,000 of their inhabitants perished. Again, in 1300, seven parishes in Nord Strand and Pellworm were destroyed; and in 1338, Ditmarsch experienced a new catastrophe, which swept away a great part of it on the side next Eyderstede: the dike of the course of the Eyder between the sand-banks was demolished, and the tides have ever since preserved their course throughout that wide space. Lastly, in the year 1362, the isles of Fora and Sylt, then forming but one, were divided, and Nord Strand, then a marsch united to the coast, was separated from it.
During a long time, the inhabitants who survived these catastrophes, and their successors, were so much discouraged, that they attempted nothing more than to surround with dikes like the former such spaces of their meadow-land as appeared the least exposed to these ravages, leaving the rest to its fate. But the common course of causes continually tending to extend and to raise the grassy parts of the sand-banks, and no extraordinary combination of circumstances having interrupted these natural operations, later generations, farther advanced in the arts, undertook to secure to themselves the possession of those new grounds. In 1525, they turned their attention to the indentations made, during the preceding catastrophes, in the borders of the marsches; the waves, confined in these narrow spaces, sometimes threatening to cut their way into the interior part. In the front of all the creeks of this kind they planted stakes, which they interlaced with osiers, leaving a certain space between the lines. The waves, thus broken, could no longer do injury to the marsch; and their sediments being deposited on both sides of this open fence, very solid fore-lands were there formed. In 1550, they raised the dikes considerably higher, employing wheelbarrows, the use of which was only then introduced. For this purpose, they much enlarged and deepened the interior canals, in order to obtain more earth, not merely to add to the height of the dikes, but to extend their base on the outer side. At last they began to cover these dikes with straw-ropes; but this great preservative of dikes was at first ill managed; and the use of it was so slowly spread, that it was not adopted in North Strand and in Eyderstede, till about the years 1610 and 1612.
Before that time, however, the safety of the extensive soil of the latter marsch had been provided for in a different manner. I have said above, that, when the isles of Everschop and Utholm had been united to it, the whole together still formed but one large island; now, in this state, it was in as great danger on the side towards the continent, as on that open to the sea; because two small rivers, the Trene and the Nord Eyder, discharging themselves into the interval between it and the land, and by preserving their course to the sea, this interval was thus kept open to tempest, sometimes from the side of the Hever, sometimes from that of the Eyder; and the waves, beating against the geest, were thence repelled upon the marsch. The inhabitants, seeing that the expence of remedying these evils would be greater than they could afford, while at the same time it was indispensable to their safety, addressed themselves to their bishop and to their prefect, of whom they requested pecuniary assistance; and having obtained it they first undertook the great enterprise of carrying the Trene and the Nord Eyder higher up into the Eyder; keeping their waters, however, still separate for a certain space, by a dam with a sluice, in order to form there a reservoir of fresh water; the tides ascending up the Eyder above Frederickstadt. They were thus enabled to carry on the extremities of the dike on both sides to join the geest; and the interval between the latter and the marsch was then soon filled up, there being only left at their junction the canal above described which receives the water of the geest, and, at low water, discharges them from both its extremities by sluices. At the same time, the islands of Pellworm and Nord Strand were united with each other by means of eight hoogs; and the sandy marsches of which I have spoken, contiguous to the geest, on the north of that of Husum, were inclosed with dikes.
After the dikes had been thus elevated, and their surface rendered firm by the straw ropes, though the latter were not yet properly fixed, the inhabitants of the marsches for some time enjoyed repose; but on the 11th October 1634, the sea, rising to an excessive height, carried away, during a great tempest, the hoogs which had produced the junction between Pellworm and Nord Strand, these having ever since continued distinct islands; it also violently attacked Ditmarsch; and its ravages extended over the whole coast, as far as the very extensive new lands of Jutland. Princes then came forward zealously to the relief of their subjects. In particular, Frederick III., Duke of Sleswigh, seeing that the inhabitants of Nord Strand were deficient both in the talents and in the means necessary for the reparation and future security of that large island, and knowing that the art of dikes had made greater progress in Holland, because of the opulence of the country, addressed himself to the States-General, requesting them to send him an engineer of dikes, with workmen accustomed to repair them; and this was granted. The dikes of Nord Strand were then repaired in the most solid manner; and the Dutch engineer, seeing the fertility of its soil, advised his sons upon his death-bed, to purchase lands and settle there, if the Duke would grant them the free exercise of their religion; they being Jansenist catholics, and the inhabitants of the island Lutherans. The Duke agreed to this, on condition that they and their posterity should continue to superintend the works carried on upon the dikes; to which they engaged themselves. From that time the art of dikes, and particularly that part of it which consists in covering them solidly with straw, has become common to all the marsches; and the Dutch families, which have contributed to this fortunate change, continue to inhabit the same island, and to enjoy the free exercise of their religion.”
Note G, p. 28.
In different parts of Scotland, as in Aberdeenshire, Hebrides, and Shetland Islands, there are examples of the natural chronometer mentioned in the text. In Morayshire there is a striking example of the sand-flood, concerning which the following details have been furnished by my young friend the Rev. Mr Ritchie.
“Westward from the mouth of the river Findhorn in Morayshire, a district, consisting of upwards of ten square miles of land, which, owing to its extreme fertility, was once termed the Granary of Moray, has been depopulated and rendered utterly unproductive by the sand-flood. This barren waste may be characterised as hilly; the accumulations of sand composing these hills frequently varying in their height, and changing their situation.
There is historical evidence, that, in the year 1097, the Moray Firth overflowed the low country on its southern shore, and threw out sand. But the destruction of the barony of Coubine (which includes the greater part of the desert mentioned above) was long subsequent to this, as might be proved from the inscription on a tombstone in the church yard of Dyke. From historical notices, also, in regard to the Kinnairds of Coubine, preparing for publication, it appears that the eruption of sand commenced about the year 1677; that its progress was gradual; that, in 1697, not a vestige was to be seen of the manor-place, orchards, and offices of Coubine; that two-thirds of the barony were already ruined, and that the sand was daily gaining ground.
This sand, which overwhelmed Coubine, came from Mavieston, situated on the shore, about seven miles west from the mouth of the Findhorn, where, from time immemorial, there have been large accumulations of sand. The sands at Mavieston had formerly been covered with vegetation. In an act of the Scottish Parliament, dated 16th July 1695, for the preservation of lands adjacent to sand-hills, it is stated, that the destruction of Coubine “was occasioned by the bad practice of pulling bent and juniper.” Having been thus set at liberty, the sand moved towards the north-east, as appears from the desolation which marks its progress. The moving cause is the wind. I have had opportunities of witnessing the effect of the wind on the loose sand. When the breeze is moderate it carries along with it successive waves of sand, each wave (if I may be allowed the expression) being of a small size, and moving with greater or less velocity, in proportion to the strength of the breeze, and presenting a very beautiful appearance. When the wind is high the heavier particles are drifted forwards, the more minute are raised to a considerable height in the atmosphere, occasioning no small inconvenience to the spectator, who finds his ears and nostrils filled with sand. The movements of the sand are still towards the north-east. In the winter of 1816 a large portion of Binsness, the only remaining farm on the west side of the Findhorn, situated in the line of the sand’s progress, was overwhelmed. Since that period large accumulations of sand have disappeared altogether, and rich soil, marked with the plough, has been left bare, after having been buried for upwards of a century.
The very minute particles, which, as has been stated, the wind raises to a considerable height, are occasionally carried across the Bay of Findhorn. In the statistical account of Dyke, the parish in which Coubine is situated, it is said, “that, at the town of Findern, in a blowing day, one may feel the sand sharply striking on his face, from the west side.” This sand, of extreme fineness, is to be seen in and around the town of Findhorn, and along the coast much rich land is said to have been covered by sand brought from the west.
The greater quantity of the sand is drifted into the river, and its effects have been very remarkable. Many years ago the mouth of the river having become blocked up with sand, it cut out for itself its present channel, which conducts it, by a more direct course, to the sea. In consequence of this, the old town of Findhorn had changed its situation, from the east to the west side of the river, and its site has since been covered by the sea. Previous to this, however, the inhabitants, carrying with them the stones of their former houses, had removed across the river, and erected the present village. On the retiring of the tide from the bay, the river almost disappears, being swallowed up by the sand, and quick-sands are formed. The effect resulting from the same cause, the drifting in of the sand is very different at high water. In consequence of the channel of the river having been filled up, the bay has increased in breadth. The sand constantly carried down by the river has formed a bar, which prevents the entrance of large vessels; and the river, probably owing to its increased breadth, and this bar depriving it of the impetus acquired in the course of its descent, is, at spring-tides, unable to force its way into the sea, when it is made to flow back, and inundate a considerable extent of carse-land situated at the head of the bay. It was at one time proposed to render the river navigable by dredging. And it is proposed to endeavour to save the adjoining carse-land, which is of the richest quality, from the monthly inundation to which it is at present subject, by building a wall along the river side.
I venture to suggest, that the plan Nature employs for fettering down sand should first be imitated, and that seeds of the Arundo arenaria, Elymus arenarius, and other plants, which grow readily in sand, should be, from time to time, strewed over the Mavieston Hills. The seeds of the Arundo arenaria are not always to be had; but plants might easily be procured in abundance, and be dibbled into the sand-hills. The circumstance of great accumulations of sand having of late disappeared from Coubine, has given rise to the expectation, that the barony is at no distant period to become again serviceable to man. By cutting off fresh supplies from Mavieston, this period would be accelerated, and the proposed improvements rendered comparatively easy.
There is at present little bent on Coubine. It is chiefly confined to a range of knolls, which forms the southern boundary of the sand, and protects the adjoining cultivated fields from its encroachments; and yet, notwithstanding the terrible calamity the inhabitants of Moray brought upon themselves, by the pulling of bent, this “bad practice” still prevails; this plant being in no other district of country which I have visited so generally employed for thatching cottars’ houses, and other economical purposes.”
In the Outer Hebrides the effects of the sand-flood are also considerable, as shewn in the following notice communicated by my intelligent assistant Mr Macgillivray.
“The bottom of the sea, along the whole west coast of the Outer Hebrides, from Barray Head to the Butt of the Lewis, appears to consist of sand. Along the shores of these islands this sand appears here and there, in patches of several miles, separated by intervals of rock, of equal or greater extent. In some places the sandy shores are flat, or very gently sloping, forming what are here called Fords; in others, behind the beach, there is an accumulation of sand to the height of from twenty to sixty feet, formed into hillocks. This sand is constantly drifting; and in several places islands have been formed by the removal of isthmi. The parts immediately behind the beach are also liable to be inundated by the sand; and in this manner most of the islands have suffered very considerable damage. Those of Pabbay and Berneray in Harris may be particularised; in the former of which, a tract of about a mile and a-half long, by half a mile in breadth, has been converted into a desert of drifting sand; and in the latter a large plain, that was formerly noted for its fertility, has been entirely swept away. The sand consists almost entirely of comminuted shells, apparently of the species which are found in the neighbouring seas. It is rather coarse in the grain; but, during high winds, by the rubbing of its particles upon each other, a sort of dust is formed, which, at a distance, resembles smoke, and which, in the Island of Berneray, I have seen driven into the sea, to the distance of upwards of two miles, appearing like a thin white fog. The cure of sand drift has been attempted in these islands in two different ways. Mr Alexander Macleod, surgeon of North Uist, is the inventor of the most efficacious method, which is that of cutting thin square turfs from the neighbouring pasture grounds, and laying them down at intervals of some inches. In the course of a very few years the turfs coalesce, and the stript ground is little the worse; for the roots remaining in it, a new vegetation rapidly springs up. The other method was introduced by Mr Macleod of Harris, and tried extensively upon his estate. It consists of planting small bundles of Arundo arenaria, at distances of about a foot and a-half. These take root, and prevent the drifting to a certain degree. But often vegetation is tardy in establishing itself, and if the turf plan be not considerably more expensive, it seems preferable, because it very effectually prevents the drift, and moreover, produces excellent pasture ground; the former of which indications, the planting system, does not completely effect, and the latter in a very imperfect degree.”
We may add, as this subject is a very interesting one, that further details, in regard to the moving sands of Scotland, will be found, on consulting the Statistical Account of Scotland, vol. xx. p. 220. In the Appendix to the Account of the parish of Dyke, vol. xx. p. 228. et seq. there is an account of the Sand-Hills of Mavieston, which overwhelmed the barony of Coubine, as mentioned in Mr Ritchie’s communication. In vol. xix. p. 622. is a notice of the shifting of two hills of the Mavieston Range 500 yards in twenty years. In vol. xxi. p. 207. is a notice of some hundred acres in Duffus’ parish covered three feet deep by drift sand; fourteen inches accumulating in one night. In Neill’s Tour in Orkney and Shetland 1804, it is observed, that, in the neighbourhood of the Castle of Noltland, in Westra, much havoc has been done by the blowing of the sand. No measures are there employed for putting a stop to this kind of devastation. In the 6th volume of the Highland Society’s Transactions will be found a report of the operations carried on in Harris, and alluded to in Mr Macgillivray’s communication. And in Dr Walker’s Account of the Hebrides, and Mr Macdonald’s Work on the Hebrides, farther details may be seen. In Jameson’s Account of the Shetland Islands, and in Shirreff and Fleming’s Reports on these islands, are also facts connected with this devastating agent. We may add, that Dr Oudney, Major Denham, and Captain Clapperton, have added to our knowledge of the blowing sands of the African deserts. The coloured engraving of the sand-hills of the African Desert in Denham, Oudney and Clapperton’s Narrative, is a striking and interesting representation of the form of the moving sand-hills of Africa.
The sands of the Lybian desert, he says, driven by the west winds, have left no lands capable of tillage on any parts of the western banks of the Nile not sheltered by mountains. The encroachment of these sands on soils which were formerly inhabited and cultivated is evidently seen. M. Denon informs us, in the account of his Travels in Lower and Upper Egypt, that summits of the ruins of ancient cities buried under these sands still appear externally; and that, but for a ridge of mountains called the Lybian chain, which borders the left bank of the Nile, and forms, in the parts where it rises, a barrier against the invasion of these sands, the shores of the river, on that side, would long since have ceased to be habitable. Nothing can be more melancholy, says this traveller, than to walk over villages swallowed up by the sand of the desert, to trample under foot their roofs, to strike against the summits of their minarets, to reflect that yonder were cultivated fields, that there grew trees, that here were even the dwellings of men, and that all has vanished.
If, then, our continents were as ancient as has been pretended, no traces of the habitation of men would appear on any part of the western bank of the Nile, which is exposed to this scourge of the sands of the desert. The existence, therefore, of such monuments attests the successive progress of the encroachments of the sand; and those parts of the bank, formerly inhabited, will for ever remain arid and waste. Thus the great population of Egypt, announced by the vast and numerous ruins of its cities, was in great part due to a cause of fertility which no longer exists, and to which sufficient attention has not been given. The sands of the desert were formerly remote from Egypt; the Oases, or habitable spots, still appearing in the midst of the sands, being the remains of the soils formerly extending the whole way to the Nile; but these sands, transported hither by the western winds, have overwhelmed and buried this extensive tract, and doomed to sterility a land which was once remarkable for its fruitfulness.
It is therefore not solely to her revolutions and changes of sovereigns that Egypt owes the loss of her ancient splendour; it is also to her having been thus irrecoverably deprived of a tract of land, by which, before the sands of the desert had covered it, and caused it to disappear, her wants had been abundantly supplied. Now, if we fix our attention on this fact, and reflect on the consequences which would have attended it if thousands, or only some hundreds, of centuries had elapsed since our continents first existed above the level of the sea, does it not evidently appear that all the country on the west of the Nile would have been buried under this sand before the erection of the cities of ancient Egypt, how remote soever that period may be supposed; and that in a country so long afflicted with sterility, no idea would even have been formed of constructing such vast and numerous edifices? When these cities indeed were built, another cause concurred in favouring their prosperity. The navigation of the Red Sea was not then attended with any danger on the coasts; all its ports, now nearly blocked up with reefs of coral, had a safe and easy access; the vessels laden with merchandize and provisions could enter them and depart without risk of being wrecked on these shoals, which have risen since that time, and are still increasing in extent.
The defects of the present government of Egypt, and the discovery of the passage from Europe to India round the Cape of Good Hope, are therefore not the only causes of the present state of decline of this country. If the sands of the desert had not invaded the bordering lands on the west, if the work of the sea polypi in the Red Sea had not rendered dangerous the access to its coasts and to its ports, and even filled up some of the latter, the population of Egypt and the adjacent countries, together with their product, would alone have sufficed to maintain them in a state of prosperity and abundance. But now, though the passage to India by the Cape of Good Hope should cease to exist, though the political advantages which Egypt enjoyed during the brilliant period of Thebes and Memphis should be re-established, she could never again attain the same degree of splendour.
Thus the reefs of coral which had been raised in the Red Sea on the east of Egypt, and the sands of the desert which invade it on the west, concur in attesting this truth: That our continents are not of a more remote antiquity than has been assigned to them by the sacred historian in the book of Genesis, from the great era of the deluge.
Note H, p. 30.
The ocean, in its action upon the cliffs and banks situated on the coast, breaks them down to a greater or less extent, and either accumulates the debris at their basis in the form of sea beaches of greater or less magnitude, or by currents carries it away to be deposited upon other shores, or to give rise to sand-banks near the coast, which, in the course of time, become united to the land, and thus secure it from the further action of the sea. These destroying and forming effects of the waters of the ocean are to be observed all around the coasts of this island; and beautiful examples of such actions are to be seen on the coasts of Ireland, and in many of the islands that lie to the west and north of Great Britain. In a paper read before the Wernerian Natural History Society, Mr Stevenson, engineer, mentions many facts illustrative of the destroying effects of the ocean on our coasts.—Thus he informs us that the waters of the sea are wearing away the land upon both sides of the Frith of Forth, not only in exposed, but also in sheltered situations, and the solid strata, as well as the looser alluvial formations, which owe their origin to the destroying agency of the ocean at a former period, are again yielding to its action. At Saint Andrew’s, the famous castle of Cardinal Beaton, which is said originally to have been some distance from the sea, now almost overhangs it: From St Andrew’s northward to Eden water and the River Tay, the coast presents a sandy beach, and is so liable to shift, that it is difficult to trace the change it may have undergone. It is certain, however, that, within this last century, the sea has made such an impression upon the sands of Barray, on the northern side of the Tay, that the light-houses at the entrance of the river, which were formerly erected at the southern extremity of Button-ness, have been from time to time removed about a mile and a quarter further northward, on account of the wasting and shifting of these sandy shores, and that the spot on which the outer light-house stood in the 17th century, is now two or three fathoms under water, and is at least three quarters of a mile within flood-mark.
NOTE, p. 32.
Of all the genera of lithophytes, the madrepore is the most abundant. It occurs most frequently in tropical countries, and decreases in number and variety as we approach the poles. It encircles in prodigious rocks and vast reefs many of the basaltic and other rocky islands in the South Sea and Indian Ocean, and, by its daily growth, adds to their magnitude. The coasts of the islands in the West Indies, also those of the islands on the east coast of Africa, and the shores and shoals of the Red Sea, are encircled and incrusted with rocks of coral. Several different tribes of madrepore contribute to form these coral reefs; but by far the most abundant are those of the genera carophylla, astrea and meandrina. These lithophytic animals not only add to the magnitude of land already existing, but, according to some naturalists, they form whole islands. Dr Forster, in his Observations made during a Voyage round the World, gives an account of the formation of these coral islands in the South Sea.
All the low isles, he says, seem to me to be a production of the sea, or rather its inhabitants, the polype-like animals forming the lithophytes. These animalcules raise their habitation gradually from a small base, always spreading more and more, in proportion as the structure grows higher. The materials are a kind of lime mixed with some animal substances. I have seen these large structures in all stages, and of various extent. Near Turtle Island, we found, at a few miles distance, and to leeward of it, a considerable large circular reef, over which the sea broke every where, and no part of it was above water; it included a large deep lagoon. To the east and north-east of the Society Isles, are a great many isles, which in some parts are above water; in others, the elevated parts are connected by reefs, some of which are dry at low water, and others are constantly under water. The elevated parts consist of a soil formed by a sand of shells and coral rocks, mixed with a light black mould, produced from putrified vegetables, and the dung of sea-fowls; and are commonly covered by cocoa-nut trees and other shrubs, and a few antiscorbutic plants. The lower parts have only a few shrubs and the above plants; others still lower, are washed by the sea at high-water. All these isles are connected, and include a lagoon in the middle, which is full of the finest fish; and sometimes there is an opening, admitting a boat or canoe, in the reef, but I never saw or heard of an opening that would admit a ship.
The reef, or the first origin of these isles, is formed by the animalcules inhabiting the lithophytes. They raise their habitation within a little of the surface of the sea, which gradually throws shells, weeds, sand, small bits of corals, and other things, on the tops of these coral rocks, and at last fairly raises them above water; where the above things continue to be accumulated by the sea, till by a bird, or by the sea, a few seeds of plants that commonly grow on the sea-shore, are thrown up, and begin to vegetate; and by their annual decay and reproduction from seeds, create a little mould, yearly accumulated by the mixture with sand, increasing the dry spot on every side; till another sea happens to carry a cocoa-nut hither, which preserves its vegetative power a long time in the sea, and therefore will soon begin to grow on this soil; especially as it thrives equally in all kinds of soil; and thus may all these low isles have become covered with the finest cocoa-nut trees.
The animalcules forming these reefs want to shelter their habitation from the impetuosity of the winds, and the power and rage of the ocean; but as, within the tropics, the winds blow commonly from one quarter, they, by instinct, endeavour to stretch only a ledge, within which is a lagoon, which is certainly entirely screened against the power of both. This, therefore, might account for the method employed by the animalcules in building only narrow ledges of coral rocks, to secure in their middle a calm and sheltered place; and this seems to me to be the most probable cause of the origin of all the Tropical Low Isles, over the whole South Sea.
That excellent navigator, the late Captain Flinders, gives the following interesting account of the formation of Coral Islands, particularly of Half-way Island on the north coast of Terra Australis[381].