cattle, and it is also used abroad for making cordage and netting.

The protection of these sand-dunes from injury, as already stated in Chapter I., was considered of such importance as to be the subject of legislative enactment.

The growth of the reed or grass can be promoted in bare places, or newly formed dunes, by removing tufts from the older dunes or the inland banks, and planting them in the sand.

On the coast of Holland the dunes are extended and repaired by setting in the sand, in rows about 1 foot apart, tufts of marramgrass. The holes are dug with the hand, the tuft placed in, and the sand pressed round it. One or two rows of reeds are set in the sand, projecting about 4 feet from the surface. The sand drifting along the beach is caught by the reeds, almost burying the tufts of grass, which soon make their way through. As the sand grows up, fresh plantings of grass and reeds are made. By this means bare places in the dunes are extended seaward, and the toe of the slope made good when it has been cut out by storms.

In heavy gales gullies are cut through the dunes, which rapidly increase in width and depth, and through which the water will be apt to run at high tides. These demand careful attention and repair, by making barriers of reeds and bushes, and replanting the marram-grass until the gap is restored. All knolls and vertical faces formed on the seaward face of dunes also should be from time to time levelled and trimmed to a gentle slope.

The bulk of the sand of most dunes is composed of grains of quartz, but in places where shell sand predominates on the beach, the dunes are also composed of this. In Jutland the bulk of the sand consists of yellow quartzite grains mixed with black titanic iron; in gales the dunes are furrowed with alternate ridges and depressions, the former composed of sand and the latter lined with the iron grains. In Prussia dunes are in places sprinkled with oxide of iron, which has given the sand a red colour.

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The size of the grains on English dunes varies from 1 to 20 of an inch, the average size being 100 of an inch in diameter. The largest grains are to be found at the base of the dune, and the finest grains at the top.

The slope and surface is greater and more regular on the lee than on the windward face of the latter, standing after a gale at an angle of from 5 to 10 degrees, the slope of the former being about 30 degrees with the horizon.

Sand-dunes are to be found on several parts of the English coast, but they do not rise so high, and are not so extensive, as on the opposite shores of Belgium and Holland.

The Lincolnshire coast is protected by a range of sandhills 30 miles in length, and from 15 to 20 feet high.

On the Norfolk and Suffolk coasts there are also long ranges of dunes, varying in height from 10 to 50 feet, which form a protection to the low land behind them. In Norfolk, churches and villages have been buried by the advancing sandhills. At Eccles, the church, at one time buried, became again uncovered owing to the sand drifting further inland.

The dunes on the South Coast are, with a few exceptions, unimportant. In the Bristol Channel, near Braunton Burrows, the sandhills are lofty and nearly a mile wide. Port Talbot, which lies open to the channel, is protected by hillocks of blown sand, which rise 50 feet above the sea. Near Ogmoor, in Glamorganshire, the dunes reach 2 miles inland, and attain a height of 150 feet, the houses adjacent being rendered uninhabitable, and the channel of the river filled up for a length of 2 miles.

In Cornwall, along the north-west coast, there are extensive dunes or "towans." In St. Ives and Perran Bays the dunes. cover several square miles, composed of shell sand, chiefly mussels. On the east of Padstow the sandhills, which consist largely of shell sand, are 100 feet in height, and a church has been buried by the sand. These sands are used largely for manure. In several places farm buildings and houses have been buried by the blown sand. At Marazion the sandhills are 130 feet high, and at Penzance 193 feet. The former sands are chiefly granitic. The ancient church of Perranzabuloe, which was buried by the drifting sand, became recently uncovered by the further advance of the dunes.

On the West Coast, the principal hills of blown sand extend between the Mersey and the Ribble, and between Lytham and Blackpool. These in places are upwards of 2 miles in width, and vary in height from 30 to 80 feet.

Along the shores of the Moray Firth and Aberdeenshire several parishes have been wholly or in part buried by sanddunes.

Barrow, a town on the east coast of Ireland, near the mouth of the river Bann, was buried beneath the sand, for many years a single chimney from one of the houses showing above the surface.

On the island of Coll, in the Hebrides, the sandhills are prevented from encroaching on the land owing to the sand being held together by the sea bent-grass (Elymus arenaria). During gales in winter the wind plays havoc with these hills, scooping out in one place a hollow 50 feet deep, and, in another, levelling the windward side to an almost vertical face; but in calm weather the damage is made good, and the sea-grasses mat and bind the shifting soil with their long spreading roots.

On the opposite side of the English Channel and North Sea the dunes extend in an almost unbroken line from Calais to the Texel, the dunes beginning soon after the chalk cliffs cease.

On the French coast they vary from a quarter to nearly a mile in width, and are from 50 to 80 feet in height; and along Belgium from 1500 to 2000 feet in width, and from 50 to 60 feet in height, the highest being over 130 feet above sea level. Holland depends almost entirely for its protection from the sea upon the sand-dunes, which are from 1 to 3 miles wide, and from 40 to 50 feet in height.

Elie de Beaumont states that on the coast of Brittany the sanddunes, which extend over a length of 12 miles, driven by the winds from the north-west, and advancing landward, rendered a canton uninhabitable by covering it with 20 feet of sand. The tower of the church and chimneys of the buried houses are now occasionally

visible.

The most striking examples of dunes are to be found on the shores of the Bay of Biscay, where the sandhills extend for 150 miles from the cliffs at Biarritz to the Point de Grave at the mouth of the Gironde, occupying an area of about 500 square miles.

Along this space at one time there existed a vast bay, having an area of 1,700,000 square miles, which became covered with sand raised above sea-level, and as bare of vegetation as the desert of Sahara. The southern portion of this vast sandy area is known as the Landes.

The dunes, which consist of a series of hills and valleys, vary in width from 300 yards to nearly 5 miles, or an average width of 3 miles, and attain a height in some parts of over 300 feet. The greatest elevation is obtained at the centre of the line of dunes, the height near the Gironde decreasing to 20 or 30 feet. The size of the grains of sand varies with the height, the smallest grains being found at the top of the highest hills.

The sand has been derived from the destruction of the cliffs, and consists almost entirely of quartz. It was estimated by Bremontier1 that five million cubic yards of sand are annually blown from the sea-beach on to and over these hills.

The sands of which the dunes consist have been described as having been thrown up from the sea, vomis par la mer. If this were so, the bed of the sea must have become deepened and lowwater line advanced landward. To a certain extent this appears to have been the case, as the ruins of an ancient town, "Novio Magus," which was situated opposite Soulac, not far from the Point de Grave, was visible at low water in the sixteenth century. Between 1830 and 1842 the Point de Grave is said to have retreated 200 yards. All the buildings at the extremity of the peninsula have had to be taken down and removed further inland, and the lighthouse at the Point de Grave now occupies its third position."

The prevailing winds on this part of the coast of France are from north-west to south-west, the heaviest seas being produced during south-west gales. The set of the flood tide is from south to north, and the littoral drift of the beach material is in the same direction, the river Gironde having been diverted from its original outfall by a bank of sand on which dunes have now accumulated.8

Until checked by the measures that were taken, the sands advanced landward at a rate estimated by Bremontier at about 35 yards a year, and by Lavalat at from 5 to 10 yards, burying in their progress, forests, farms, vineyards, villages, and churches. Some of these, after being buried for years, were again uncovered, owing to the sands moving inland. Thus the old village of Soulac, which stood half a mile from the shore, was at one time buried and then uncovered, and where it once stood there was only a sea of sand. A dune 20 yards wide was advancing towards the village of Mimizam in 1830; as it advanced, villages which had been buried became uncovered. The market town of Beas and the village of St. Julien, with its church and vineyards, were buried at the beginning of the nineteenth century by sand and

1 "Annales des Ponts et Chaussees, 1883." Mémoire by M. Lefort, 1831, and by M. Bremontier, 1833, on the dunes of the Coast of the Gironde; and the Landes of the Gulf of Gascony by M. Laval, 1847. "Leçons de Geologie Pratique," L. Elie de Beaumont. Paris, 1845.

2 "Man and Nature." Marsh. London, 1864.

3 "Étude sur les Rivieres à Marée, et sur les Estuaires," par H. L. Partiot. Paris, 1892.

water held up by the dunes. The old Roman road leading from Bordeaux to Bayonne was also engulfed; and the church of Legé, taken down at the end of the seventeenth century and rebuilt 2 miles inland, had again to be removed 160 years afterwards, showing an advance of the sands at the rate of 27 yards a year.

During heavy gales between north-west and south-west, the sands off the shore are drifted in such quantities landward as to obscure the atmosphere, and the breathing of men and animals is very painful, the fine grains of sand filling the ears and blinding any person who does not keep the eyes shut. If refuge be taken on the lee side, the risk is run of being buried alive in the sand. It is recorded that a pastor of one of the villages, overcome by fatigue, laid down to rest at the foot of the dune of Larreillet, and his dead body, buried in the sand, was not discovered until some time afterwards.

The dunes running in a continuous line parallel with the shore have cut off the streams which drained the land and emptied into the sea. The consequence is that large inland lakes, or "etangs,' have been formed, the surface of which is considerably above the sea-level. The largest of these lakes, that of Cazan, has a width of nearly 7 miles and a depth of 130 feet, the bottom being 80 feet below sea-level. Over a length of 100 miles between the mouth of the Gironde and Mimizan, in the Bay of Arcachon, there are only two places where the water draining from the land has an outlet to the sea.

About the end of the eighteenth century steps were taken, under the direction of the French Government, to arrest the landward progress of the dunes by planting firs, and a sum of £5000, afterwards increased to £20,000, appropriated for the purpose. Two methods were adopted, one by covering the face of the dunes with branches of pines or broom, and the other by fixing palisades made of faggots of the same material in the form of a series of isosceles triangles, and making seed-beds of pines in the shelter afforded. The fir which has been found to thrive best, and to be most successful in confining the sand and yielding the largest pecuniary returns both as timber and from its resinous products, on the sands is the Pinus maritima. The sea lyme-grass (Elymus arenarius) was also planted. The seed pines acquired a height of 15 to 16 feet at the end of four or five years.

About 200,000 acres of sand-dunes and sand-hills have been