264 PROF. A. H. GREEN ON THE GEOLOGY AND 



tainedfrom the Ecca Beds near Beaufort West. I have accordingly 

 ventured to show Ecca Beds rising to the surface in the valley of 

 the Orange Eiver, where it is crossed by Section 2 (fig. 5). 



Mr. Dunn's main argument in favour of the Kimberley Shales 

 being identical with the Ecca Beds is that he has succeeded in tracing 

 the Dwyka Conglomerate northwards up to the neighbourhood of 

 Kimberley, and that the Kimberley Shales there lie directly upon 

 it. If this point be substantiated, it will tell very strongly in favour 

 of Mr. Dunn's view. But I must say that I distrust his identifi- 

 cations. 



Eor instance, the sides of the Kimberley Diamond Pipe show the 

 following section : — 



feet. 



Surface and debris 24 



Shale 277 



Breccia 3 



Dolerite, not bottomed ia 1882, about 100 



The Dolerite has been already described (see page 254), and has 

 all the characters of the intrusive sheets so common in the Kimberley 

 Shales ; I saw no reason to think it was anything else. Mr. Dunn 

 however calls it " Ancient Diabase," and believes that the thin band 

 of breccia above it is the representative of the Dwyka Conglomerate. 

 I do not think he will find many supporters in this view. 



There is further the possibility that the conglomerate identified by 

 Mr. Dunn with the Dwyka Conglomerate is what I have called 

 " The Basement Conglomerate of the Kimberley Shales." 1 know 

 this bed only from Mr. Stow's description* ; but his account is very 

 clear, and seems to show that this conglomerate not only lies 

 underneath, but is partly interbedded with his " Olive Shales." The 

 materials of the two conglomerates must have been derived from 

 the crystalline rocks of the Transvaal, so they would necessarily be 

 hard to tell one from another. My notion of the relation of the 

 two conglomerates to one another is shown at the northern end of 

 Section 2 (fig. 5).^ 



The considerations just adduced and others of a similar character 

 show that there is much that is uncertain in Mr. Dunn's reading. 

 But the point on which I rely is, that I believe that beds having 

 all the characters of the Kimberley Shales crop out on the southern 

 side of the Nieuwveldt and Camdeboo Eange, between the Karoo 

 and Ecca Beds. If this belief turn out to be well founded, Mr. 

 Dunn is certainly mistaken. 



III. Miscellaneous. 



Conglomerates of the OlipTiants River (Section 3, fig. 6). — Mention 

 must be made of some red sandstones and conglomerates which I saw 

 in the valley of the Oliphants River. They lay at various levels, and 

 rested on Bokkeveldt Beds. All the pebbles I saw in the conglom- 

 erate were of quartzite, like that of the adjoining hills, the majority 



* Quart. J(jurn. Geol. Soc. vol. xxx. (1874), p. 598, pi. xxxix. fig. 2. 



