We halted in a hollow place near the highest point, where we strangely omitted to take observations for altitude; and after a slight repast hurried down the slope in a SSE. direction, towards the valley of the Tetuan river. We here enjoyed a fine view of the snow-streaked mass of the Riff Mountains, which we may call, from their best known peak, the Beni Hassan Group. The mountain ranges of the Riff—extending for about 180 miles from Tetuan to the mouth of the Oued Moulouya, which lies very near the French frontier—undoubtedly form a part of the system of the Lesser Atlas of Algeria; but, if we may trust the maps and such scanty reports as can be picked up, they constitute a separate group, not continuous with the coast range of Western Algeria. The true relations between the main range of the Lesser Atlas of Algeria and the diverging ranges of the Great Atlas that extend over the region S. and SE. of Fez must remain unknown so long as the latter region remains inaccessible to European travellers. The river Moulouya and its eastern branch, the Oued Za, mark the existence of two considerable valleys, and it is probable that the very sinuous course laid down for both those streams in the French map may be founded on native reports approximately correct; while it is quite certain that the adjoining mountain ranges as shown on that map differ very widely from the truth. A traveller going from Fez to the mouth of the Oued Moulouya, in a direction slightly north of due east, traverses a broad valley, with the Riff Mountains on his left, lying between him and the Mediterranean coast, and the northern branches of the Great Atlas on his right. Somewhere near Theza he reaches the watershed between the region that is drained towards the Atlantic through the Oued Sebou and the basin of the Oued Moulouya, but seemingly without having to make any considerable ascent. He descends to the Moulouya—or rather he would do so if the powerful Halaf tribe, who hold that region, allowed strangers to pass—where that river, after cutting its way through the unknown region between the Great and Lesser Atlas, enters a wide plain, some forty or fifty miles in extent each way. Before reaching the sea, the valley is again narrowed. On one side is the eastern extremity of the Riff Mountains, and on the other a range of lofty hills that may be considered as spurs of the Lesser Atlas of Algeria.