The southern declivity of the Atlas of Morocco sends to the Sahara, in lat. 32°, a river, the Quad-Dra (Wady-Dra), which for the greater part of the year is nearly dry, and which Renou (Explor. de l’Alg. Hist. et Geogr., T. viii. p. 65-78) considers to be a sixth longer than the Rhine. It flows at first from north to south, until, in lat. 29° N. and long. 5° W., it turns almost at right angles to its former course, runs to the west, and, after passing through the great fresh water Lake of Debaid, enters the sea at Cape Nun, in lat. 28° 46′ N. and long. 11° 08′ W. This region, which was so celebrated formerly in the history of the Portuguese discoveries of the 15th century, and was afterwards wrapped in profound geographical obscurity, is now called on the coast “the country of the Sheikh Beirouk,” (a chief independent of the Emperor of Morocco.) It was explored in the months of July and August 1840, by Captain Count Bouet-Villaumez of the French Navy, by order of his government. From the official Reports and Surveys which have been communicated to me in manuscript, it appears evident that the mouth of the Quad-Dra is at present very much stopped up with sand, having an open channel of only about 190 English feet wide. A somewhat more easterly channel in the same mouth is that of the still very little known Saguiel el-Hamra, which comes from the south, and is supposed to have a course of at least 600 geographical miles. One is astonished at the length of these deep, but commonly dry river beds. They are ancient furrows, such as I have seen in the Peruvian desert at the foot of the Cordilleras, between those mountains and the coast of the Pacific. In Bouet’s manuscript “Relation de l’Expédition de la Malouine,” the mountains which rise to the north of Cape Nun are estimated at the great elevation of 2800 metres (9185 English feet).