208 THE OCEAN. 



obliged to descend towards the plains of the interior, taking the 

 crests from the hills previously formed. In Africa, on the low shores 

 where the ocean bathes the great desert of Sahara, the enormous 

 quantity of sandy materials that the eastern winds bring from the 

 desert, and which the west wind drives back to the interior, permit, 

 it is said, the dunes of Cape Bojador and Cape Yerde to attain an 

 elevation of from 390 to nearly 600 feet.* 



The highest dune in the New World is perhaps that of Morro- 

 Melancia, near Cape St. Roch, nearly loO feet high ; it rests on one 

 side against a wooded hillock. 



To the eyes of a traveller accustomed to the ascent of the Alps 

 and the Pyrenees, these are very humble summits ; yet these heights 

 of sand assume the aspect of actual mountains, and their chains, 

 arranged parallel to the shore, like ranges of enormous waves, seem 

 to constitute an entire orographical system. Their bold taluses, their 

 solid ridges, cut as with a chisel, the regular form of their tops, 

 the general harmony of their contours, unceasingly varied at the 

 will of the wind, give them an astonishing appearance of grandeur. 

 The very even base-line which the sea-shore presents likewise aids 

 to the illusion by contrast, and contributes to the grand aspect 

 of these white hills. The old name, at once Celtic and Latin, of 

 the dunes (dun), which was applied to mountains and steep hills, 

 and which we still find in the names of several towns — Yerdun, 

 Loudun, Issoudun, Saverdun, proves that our ancestors had been sin- 

 gularly struck with the bold form of the sandy hillocks of the coast. 



While gaining incessant^ on the plains of the interior, the dune 

 buries, without destroying, all solid objects, stones, rocks, trunks of 

 trees, or human dwellings. Sometimes even it entirely covers pools 

 of water, and causes them to disappear for some time under its 

 sloping talus. When the sand brought by the wind falls regu- 

 larly on a sheet of water, stagnant or covered with scum, it often 

 forms a fine layer, completely veiling the water which bears it, 

 from view. This bed can become solid enough to remain in equi- 

 librium even when the level of the sea falls below it, and soon 

 the particles of sand, dried by the solar rays, no longer betray the 

 existence of the hidden pitfall. The herdsman or animals which set 

 foot on the surface of the hloiise are suddenly engulfed more or less 

 deeply, and the waters of the pool rise around them. Most fre- 

 quently they escape with the fright. Little by little the crumbling 

 sand is heaped up; they allow the bottom to be consolidated, then 

 * Carl Eitter, Afrika. 



