530 PKOCEEDINGS OF THE GEOIOGICAL SOCIETY. 



central point at the top (see map, fig. 10). There is no displacement 

 or alteration in the composition of the strata where they come into 

 contact with the dykes. Dr. Rubidge thought that snch dykes were 

 formed by cracks due to the shrinking of the strata, and filled up in 

 the same manner as deposits are supposed to take place in some 

 mineral veins. 



The combined thickness of strata in the two sections (figs. 8 and 

 9) amounts to about 1200 feet for this portion of the Dicynodon 

 or Karoo formation ; but this is evidently but a very small part of 

 their entire thickness ; for, taking the dip from the Zwart Kei to the 

 Stormberg, at angles varying from 4 to 7 degrees towards the N.W., 

 and on the Dordrecht side of these mountains, dipping at the same 

 angles towards the S.E., it is highly probable that the central 

 thickness of this portion must be enormous. Very little will be 

 known of their true history until the sections of every intervening 

 mountain-side are fully described. Some time, however, must elapse 

 before this can be accomplished, as many parts of the country are still 

 occupied by the native tribes. 



Dr. Livingstone's discoveries seem to throw some light on the 

 origin of this formation, viz. an elevated plateau, with successive 

 chains of lakes and marshes, that have been silted up, and subse- 

 quently the basins we find in the present day denuded out of the 

 strata thus formed. 



Accompanying the fossils mentioned in this paper, I have sent a 

 packet given to me by Mr. C. W. J. Powell, and collected by him 

 near the Upper Zwart Kei*. The large skull, so remarkable for 

 its peculiar rows of small teeth (D. S. 41 . Probably Labyrinthodont. 

 — T. R. J.), was also found in the same neighbourhood by Mr. 

 Powell ; but I am not able to point out the exact strata from which 

 any of these were obtained. I have also enclosed casts of stems 

 from Kneehalter's Neck, given tome by Mr. John M'Donaldf. 



Section of the Stormberg on the Rlaas-Smifs River. — After finish- 

 ing my account of the Dordrecht and Zwart Kei sections, I obtained 

 much valuable information with regard to a section of part of the 

 south face of the Stormberg from Mr. Charles Evans J, who has ex- 

 plored a large portion of the range in search of coal. 



This section (fig. 11) illustrates some of the strata between the 

 other two, near the synclinal axis of what I will term " the great 

 Stormberg basin"§. 



* No. 1. Eippled, fine-grained sandstone. 2. Ferruginous sandstone, with 

 obscure surface-marks. 3. Very fine-grained sandstone, bearing mud-ripples. 

 4. Sandstone, with cast of Calamites or Eguisetites ? 5 and 6. Obscure casts. 

 — T. E. J. 



t Nos. 7, 8, and 9. Sandstone casts of small portions of striated stems 

 {Eqwisetifes or Calamites ?). — T. E. J. 



X For some notes by Mr. Evans of Queenstown, on the Coal of the Storm- 

 berg, see the ' Mining Journal.' Jan. 14, 1871. — T. E. J. 



§ It is worthy of remark that, as in other instances more numerous than they 

 were once thought to be, the Stormberg range is a synclinal mountain ; for, as has 

 been shown at Dordrecht, Buffel Dooms Hat, &c., the strata of the north and 

 south dip towards and into it. 



