m. viii. PORPHYRY ROCKS. 197 



The rock was now porphyry of a prevailing red colour, 

 which, with occasional intrusive masses of diorite and dark 

 greeu basalt, makes up the whole mass of the central 

 ridge of the Great Atlas in this part of the chain. As 

 compared with the rich and varied flora, insect life ap- 

 peared, at least at this season, to be remarkably scarce, 

 and the only butterfly noted was Papilio podalyrius. 



The porphyry rocks a2Dpeared to be very hard, and far 

 less yielding to erosion than those of somewhat similar 

 character in South Tyrol. Hence the gullies and ravines 

 cut by the water channels, round which the track wound, 

 were not nearly so deep as those that add so much to the 

 picturesqueness of the scenery, and at the same time to the 

 length of the way for a traveller traversing the valleys near 

 Botzen. After winding along the slopes for several miles, 

 our track descended a little to approach once more the 

 channel of the torrent. The valley was still narrow ; but 

 the inclination of its bed was much less, and the ground 

 on either bank left space for a track, and in places even 

 for a strip of cultivation. The natives seem to be quick 

 at availing themselves of every spot possible for agricul- 

 ture. Eye and barley were here seen in ear, and the olive 

 extends very nearly to 5,000 feet above the sea, or con- 

 siderably higher than it does on the flanks of the Lebanon. 



As our track ran along the bank of a slender water- 

 course, it was completely overarched by a row of elder 

 trees in full flower, that forced us to lay our heads upon 

 our horses' necks, one of many instances of the meeting of 

 the common plants of Northern Europe with very different 

 endemic forms that characterise the upper region of the 

 Great Atlas. Some conspicuous plants of the lower country, 

 and notably Adenocarpus anagyrifolius and Linaria 

 ventricosa, extended thus far up the valley ; and these, 

 together with a wild Isatis, scarcely different from the 

 dyer's woad, gave a prevailing golden hue to the neigh- 

 bouring slopes. A reach of the valley now opened before 

 us, backed by a stern range of dark red bare rocky 



