Vol. 55.] GEOLO&Y OF SOTJTHERI^ MOROCCO AXD THE ATLAS. 209" 



Gindafy forms a cleft in tlie very heart of the Atlas, the central 

 mass being excavated till its sides alone remain, like the lips of an 

 oval cup, forming on the north the mountain-ridge of Jebel Tezah, 

 and on the south that of Wishdan, both reaching a height of 10,000 

 feet above sea-level. The outlet of this glen is the deep gorge of 

 the Wad jS'yfis. 



Geologically, however, the most remarkable feature of this 

 mountain fastness is the occurrence of red flaggy sandstones with 

 numerous angular pebbles scattered throughout them. These cling 

 to the northern side of the valley, at an angle corresponding with 

 the slope of the mountains, and seemingly bend round in a sharp 

 syncline, to occupy a similar position on the opposite side of the 

 valley. 



It would be difficult to account for the occurrence of this curious 

 sandstone-pocket in the very heart of the mountains. Can it be 

 that it was deposited in a small lake or tarn, say thrice or four 

 times as large as the present area of Gindafy, in which floated masses 

 of ice laden with angular pebbles from the mountain-sides ? If so, 

 one must also be prepared to admit that a lateral movement of the 

 opposing mountains followed the deposition of the sandstones, 

 whereby they approached each other, contracting the valley of 

 Gindafy to its present width and forming the syncline in which 

 the sandstones lie. 



Descending into the valley, the traveller finds, near the entrance 

 of the gorge which cuts through the northern mountain- barrier, a 

 deposit of huge boulders and shingle more than 100 feet thick,, 

 due, I believe, to glacial action ; though it may have arisen by an 

 accumulation of river-drift, caused by a temporary block in the 

 gorge. The latter may be the real origin of the deposit, although, 

 judging from the cursory examination that I was able to make of it, 

 I am disposed to adopt the former theory. Crossing to the southern 

 side of the small valley, one obtains a splendid insight into its 

 geological constitution, thanks to the canon-like gorge of the Wad 

 Agandice, one of the chief tributaries of the Nyfis, which it joins in 

 the valley of Gindafy, close to the gorge which drains that valley. 



In the immediate vicinity of the entrance to the Agandice caiion 

 a trachyte-dyke breaks through the red sandstones, which, as on 

 the northern side of the valley, may be seen resting upon the meta- 

 morphic rocks. The latter are largely composed of crystalline 

 limestones,- much crumpled and foliated, but chiefly ridged up in 

 vertical beds. The limestones extend for more than a mile up 

 the Wad Agandice, forming the northern half of Jebel Wishdan. 

 Then, almost at the centre of the mountain, an abrupt change takes 

 place : the traveller leaves the metamorphic area, to find himself 

 once more among the Cretaceous rocks, here dipping northward at 

 angles of 25° to 30°, in great massive beds of yellowish sandstone 

 and purple or blue shaies intercalated with thick beds of lime stone 

 At the point of junction of the two widely different formations, the 

 AVad Agandice has cut a section several thousand feet deep, right 

 across the mountains. A mile or more farther up the caiion, a 

 Q. J. G. S. No. 218. p 



