Notes on the Geology of the Drakensbergen. 425 



like the other amygdaloids formed a narrow cliff at the head of the 

 Giant's Castle Pass, and seemed to be a dyke of very slaty stuff, 

 with distinct slaty cleavage. 



I saw no evidence of glaciation in any of the portions which I 

 visited. 



The amygdaloids which compose this enormous plateau and cliff 

 faces vary considerably. 



The lowest have a dark, tough crystalline matrix full of milk-white 

 striated zeolites of all sizes — from a pin's head to three inches in 

 diameter. These occur at the top of the pass as well as at the 

 bottom. One variety has a bright red matrix, and is the toughest and 

 hardest rock to break of any in the Berg. I could not find it in 

 position, but only as boulders in the gullies and streams, of which 

 it composes about 5 per cent. Another kind is reddish brown, 

 highly crystalline, and full of small oval zeolites, many of them 

 transparent or very nearly so. It is a hard rock and rings to the 

 hammer, but is not so tough as the other two, and seems to decom- 

 pose more readily. When much weathered it turns a pale sage- 

 green. In the Berg all the peaks are composed almost entirely of 

 this rock. In places it forms square-edged walls and causeways of 

 large, rectangular blocks that look as if they had been built by giants. 

 It seems the most commonly occurring of all. I found cliffs near 

 the bottom and at various places going up, as well as on top. A 

 fourth kind exhibits a more pumice-like appearance on the outer 

 weathered crust, the zeolites, &c, having been eroded out of the 

 steam holes. It is a fairly tough rock inside, but the outer crust is 

 friable. It contains but few amygdules, weathers into round masses, 

 and peels away in rings like many of the dolerites I have seen in the 

 railway cuttings. I noted it in many places, but never above the 

 pass. A fifth sort differs considerably from the others ; it is less 

 crystalline, is not tough, but crumbles fairly easily into irregular 

 nodules which are a little harder individually than the mass of which 

 they form part. It contains quantities of white inclusions, whicb 

 are rather hard and frequently stained green. 



Some of these cliffs and masses of rock seem to show a rough 

 kind of bedding with a slope downwards towards Natal, but this was 

 not distinct. 



At Champagne Castle the Drakensbergen are 7,000 ft. above the 

 valley immediately below, and a little less at the Mont aux Sources. 

 I have seen nothing in Europe resembling the five miles of canon 

 below the Tugela Falls. In places it is not more than forty feet 

 wide, and the only route is the river-bed itself, up which four hours' 



