244 PROF. A, H. GEEEN ON THE GEOLO&Y AND 



the great freshness of the felspar-fragments as supporting this inter- 

 pretation. The absence, so far as toe Jcnow, of any associated lava- 

 flows, and of lapilli in the slides, tells somewhat the other way ; but 

 these points of negative evidence do not count for much in the 

 present limited state of our knowledge. 



(6.) The Ecca Beds consist very largely of hardened sandy clays 

 without lamination^ which 1 will call " mudstones,'' to distinguish 

 them from laminated clays or " shales ; " these are generally 

 purplish or mottled, but occasionally of other colours. Shales do 

 occur, but they are comparatively rare. The group also contains 

 much sandstone ; many of the sandstones are highly quartzose, finely 

 grained, compact and hard, approaching quartzites ; some of the- 

 sandstones exhibit very marked spheroidal weathering, so perfect 

 indeed, that any one looking at them from a little distance would 

 unhesitatingly pronounce them to be basalt or dolerite. The first 

 instance I saw of this was in the Ecca Pass ; it was so marked in 

 its character and the resemblance to weathered basalt was so close^ 

 that I could scarcely believe my eyes, when, on breaking into the 

 rock, I found it only sandstone. In some places, as between Prince 

 Albert and Prince-Albert-E-oad Station, sandy limestones occur in 

 the Ecca Beds. 



There is a most magnificent section of this group in the Ecca Pass^ 

 to the north-east of Grahamstown, which I saw under the kindly 

 guidance of Dr. Atherstone, all but clean cut from top to bottom, 

 and showing nearly 4000 feet of beds. This is not the full thick- 

 ness, for the formation extends some way further to the north-east ; 

 but as the beds are there repeated in folds, it is not easy to estimate 

 the additional thickness. 



I could hear of no fossils from the Ecca Beds. I believe reptilian 

 remains have been picked up in the country occupied by them; but, 

 from all I could learn, I came to the conclusion that these were 

 found in loose blocks on the surface, stray remnants of the sheet of 

 Karoo Beds, which once spread over the country but which has 

 been denuded away. Bain states that at Ecca Heights (north of 

 Grahamstown) a stratum occurs, nine inches thick, entirely composed 

 of vegetable remains {loc. cit. p. 54). I think the rock of this 

 locality belongs most probably to the Ecca Beds ; but I am not sure, 

 it may be a bed in the Zwarteberg quartzites. He also mentions a 

 bed, near the base of the group, which contains abundance of plant- 

 remains (Joe. cit. p. 187) ; but I have not been able to learn that any 

 of these have been determined. Cohen states that grauwacke-like 

 sandstones with indistinct plant-remains occur in the Ecca Beds 

 {loc. cit. p. 209). 



(7.) The beds which I have placed in a separate group under the 

 name of " Kimberley Shales " consist principally of grey and dark 

 sandy shales and mudstones ; some thin bands, more sandy than the 

 generality of the beds, approach sandstones ; but true sandstones are 

 either absent or rare. Thin layers of argillaceous limestone are not 

 uncommon. I shall be better able further on to explain my reasons 

 for thinking that these beds are sufficiently important and persistent 



