In sandy and gravelly ground, as the particles may be considered insoluble in water and as possessing no cohesion, grass, if it will grow, having deep roots is to be preferred, even if passing through any earth that has been placed upon a slope, in order to counteract the want of cohesion by a greater hold in the soil and any peeling of the turf or tufts forming or becoming detached, rolling down and leaving an unbared surface. Bent-grass will usually grow on most sandy soils, and a shrub known on the north-east coast of England as the sea buckthorn also rapidly vegetates, but marine grasses must be used in ground impregnated with brackish or sea water. To prevent light sand from being scattered by the wind or washed away a species of rush (Bot. _Ammophila arundinacea_) has been used in Holland and England, and is found to flourish in dry soils, and as it has spreading roots which often grow to a length of 20 feet or more it binds the grains of sand. Experience in Holland has shown that grass upon sea embankments does not grow well or flourish at a steeper slope than about 6 to 1. In countries where wind storms occur, or the soil is of so light a character that the passage of a train at considerable speed raises the earth and moves it as dust, a covering of fine grass indigenous to the country has been found to be a protection and necessary to economical maintenance. Planting the white basket willow, or withy, has been recommended as a means of preventing slips in loose soil, as the roots form a network and bind the earth and cover the surface with shrub growth. In damp ground the cuttings need not be planted as deeply as in dry earth, but of course they will not flourish in all soils. Osiers have also been adopted with good results in damp places. Embankments of blown or drift sand, easily moved by the wind, have also been protected and maintained by branches of trees laid horizontally. They were placed in regular courses alternately with a stratum of sand, the ends projecting over and down the slopes, which were sown with indigenous plants that it is known will flourish upon it. Great difficulty had been experienced in maintaining the embankment until its surface was so shielded. Sandy dunes have also been prevented from slipping and being eroded and destroyed by the sea and wind by reducing them to the same line, level, and slope, by filling all openings or depressions, or, if curved, by trimming them to a regular exterior and the largest radius, and by a covering of fascine work in the exposed places, and in any less exposed situation by planting them with grasses that will grow upon such soil, the object being to remove all local obstruction to wind or wave force and cause equable resistance and protection. In France, the drifting of blown sea-sand into cuttings, which not only may interfere with the free traffic but also be a destructive agent to the rolling stock, has been prevented by planting pine trees upon the cess.