Sand and sand alone constitutes the soil-substance of Doñana, overlying, presumably, the buried alluvia beneath. Yet a wondrous beauty and variety of landscape this desolate region affords. From the river's mouth forests of stone-pine extend unbroken league beyond league, hill and hollow glorious in deep-green foliage, while the forest-floor revels in wealth of aromatic shrubbery all lit up by chequered rays of dappled sunlight. Westward, beyond the pine-limit, stretch regions of Saharan barrenness where miles of glistening sand-wastes devoid of any vestige of vegetation dazzle one's sight--a glory of magnificent desolation, the splendour of sterility. To home-naturalists the scene may recall St. John's classic sandhills of Moray, but magnified out of recognition by the vastly greater scale, as befits their respective creators--in the one case the 100-league North Sea, here the 1000-league Atlantic. Rather would we compare these marram-tufted, wind-sculptured sand-wastes with the Red Sea litoral and the Egyptian Soudan, where Osman Digna led British troops memorable dances in the 'nineties--alike both in their physical aspect and in their climate, red-hot by day, yet apt to be deadly chilly after sundown. Resonant with the weird cry of the stone-curlew and the rhythmic roar of the Atlantic beyond, these seaward dunes are everywhere traced with infinite spoor of wild beasts, and dotted by the conical pitfalls dug by ant-lions (_Myrmeleon_). [Illustration: IN DOÑANA.] Between these extremes of deep forest and barren dune are interposed intermediate regions partaking of the character of both. Here the intrusive pine projects forest-strips, called _Corrales_, as it were long oases of verdure, into the heart of the desert, hidden away between impending dunes which rear themselves as a mural menace on either hand, and towering above the summits of the tallest trees. Nor is the menace wholly hypothetic; for not seldom has the unstable element shifted bodily onwards to engulf in molecular ruin whole stretches of these isolated and enclosed _corrales_. Noble pines, already half submerged, struggle in death-grips with the treacherous foe; of others, already dead, naught save the topmost summits, sere and shrunk, protrude above that devouring smiling surface, beneath which, one assumes, there lie the skeletons of buried forests of a bygone age. All along these lonely dunes there stand at regular intervals the grim old watch-towers of the Moors, reminiscent of half-forgotten times and of a vanished race. Arab telegraphy was neither wireless nor fireless when beacon-lights blazing out from tower to tower spread instant alarm from sea to sierra, seventy miles away.