258 PKOF. A. H. &EEEN ON THE GEOLOGY AND 



to enable me to decide whether or not the Table-Mountain Sandstone, 

 the Bokkeveldt Beds, and the Quartzites follow one another in con- 

 formable succession. But I think I obtained evidence which points 

 to a very decided unconformity between the Quartzites and the 

 Dwyka Conglomerate. No sections that I saw gave much informa- 

 tion on this point. Dr. Atherstone very kindly guided me to several 

 places in the neighbourhood of Grahamstown where he hoped we 

 might find a junction between these two formations, but the sections 

 were none of them satisfactory. This was also the case when I 

 crossed the junction near Yogel-struis-Laagte, on my road from 

 Aberdeen to Willowmore. In both cases I believe the Conglomerate 

 was folded in among the Quartzites in the way shown in Sections 3 

 and 4 ; and even if an actual junction had been visible, the disturb- 

 ance was so great that it is doubtful whether it would have been 

 possible to decide whether it was a conformable junction or not. 



At one spot only, about two miles south of Prince Albert, was I 

 lucky enough to see the Conglomerate actually in contact with the 

 underlying rock, here Bokkeveldt Beds. There were here strong 

 indications that the Conglomerate rested on an eroded surface of 

 shale ; but the exposure was far to small to allow of any general 

 conclusions being drawn from it. But, though my sections were 

 inconclusive, the following considerations, I think, will establish my 

 point. Boulders of a rock which I could not distinguish from the 

 Quartzite of the Wittebergen are plentiful on the Conglomerate ; 

 and the Conglomerate rests sometimes on Quartzite and sometimes 

 on Bokkeveldt Beds. These facts make it pretty clear that there 

 must have been very large denudation of the underlying rocks before 

 the formation of the Conglomerate. 



The next question that presents itself is whether the Ecca Beds 

 are conformable to the Dwyka Conglomerate. I saw the actual 

 junction between these two formations only in the section given in 

 fig. 2, to which I was guided by Mr. T. Bain. There could be no 

 doubt that at the point marked A the Ecca shales rested on a very 

 wavy and uneven surface of Conglomerate. But this obviously 

 proves nothing in the case of a rock like the Conglomerate, liable to 

 be thrown down in heaps ; and the apparent discordance is quite as 

 likely to be due to original irregularity of deposition as to subsequent 

 denudation . 



The only other section I saw which at all bears on the question 

 is on the north of Grahamstown, at the 10th milestone on the Queen's 

 Eoad, just at the top of the Ecca Pass, which I examined in company 

 with Dr. Atherstone. My reading of this section is given in Section 

 4 (fig. 7), and shows EccaBeds resting directly on rocks belonging to the 

 Quartzite group without any Dwyka Conglomerate between the two. 

 The Conglomerate is seen in great force not 20 yards away, so that 

 its absence can hardly be owing to irregular deposition, and would 

 seem to indicate unconformity ; but my visit to the spot was made 

 quite at the beginning of my trip, before I had become familiar with 

 the South- African rocks, and I do not insist on my interpretation. 

 The section deserves careful study by local geologists. 



