STOW SOtTTH- AFRICAN GEOLOGY. 511 



The strata of the Government Saltpan seem to follow, with (accord- 

 ing to Dr. Atherstone) Trigonia, Turritella, Ostrea, and Cidaris 

 jpustulifera. At the Bethelsdorp pan G. pusticUfera is found in the 

 greatest abundance ; and spines and plates of the same Cidaris, 

 found scattered on the sides of the outlier at the Salt Vlei, near 

 Port Elizabeth, indicate the position of the associated clays on the 

 opposite side of the Vlei (Section 0, fig. 4), with their innumerable 

 specimens of small Ostrea unmixed, as it seems at present, with 

 the remains of Cidaris. As I have already said, so little is yet ac- 

 curately known of the fossil contents of all these different strata 

 that nothing can be done to decide the question of position with any 

 degree of certainty until the fossils shall have been more fully 

 studied and classified. 



On looking at these collated sections (fig. 6) we at once see how 

 much they differ from the apparent uniformity of the sandstones of 

 the Zwartkops and Sundays Rivers (Sctions A-G, fig. 3). These 

 latter exhibit the features of an extended and uniform deposit, while 

 the former display local differences of a very diversified character. 

 Further, the more I have studied them the more I have been im- 

 pressed Aviththe idea that the position at present assigned to them * 

 is not correct. 



The following reasons may be given to explain this opinion. It 

 is said that these strata are an earlier formation than those of 

 the Zwartkops and Sundays Rivers series ; but has this been con- 

 vincingly proved '? As far as I could obtain information, no good 

 section has yet been pointed out (that is, anywhere between the 

 quartzite hills of Port Elizabeth and the Grass-ridge) where these 

 clays &c. are so situated as to demonstrate distinctly that they are 

 really beloAV, and the Zwartkops Trigonia-hedis above. Even should 

 we find them in a depression apparently lower, still this would prove 

 nothing without a satisfactory j miction in which the Trigonia-'heds 

 could be shown to be placed above the stratified clays ; whereas 

 sections have been found the reverse of this. It might as well be 

 argued that the red clay (g, g, in Section 0, fig. 4) spread over the 

 surface in different parts of the Oliphants-Hoek and Port-EKzabeth 

 Divisions, instead of one of the most recent clays, is a very ancient one, 

 because in the former locality it has been found (in sinking wells) 

 to be upwards of 100 feet in depth, and in the latter, near the New 

 Prison, about 70 feet — lower levels than either the sandstones or 

 stratified clays have been found at. This clay has evidently been 

 deposited in hollows, eroded out of the more ancient rocks ; and in 

 the same way, I cannot help thinking, these " Saliferous Strata " 

 have been deposited in positions where denudation had removed 

 some of the earlier formations. This was especially the case where I 

 examined the strata of the Government Saltpan ; for there these rocks, 

 as far as I could judge, when the dip of the ^r«/onm-sandstones is 

 taken into consideration, must be placed above those of the Zwart- 



* That is, below the great Trigonia- and AmmooiiteS'SeTies of the Uitenhage 

 formation. See Atherstone, he. cit., and Quart, Journ. Greol. Soc. vol, xxiii. p. 

 149.— T. H. J. 



