512 PEOCEEDINGS OP THE GEOLOGICAL SOCIETY. 



kops. Again, as a proof that their position is below the Zwartkops 

 Trigonia-'beds, it has been stated that these saliferous rocks are found 

 resting un conformably on the quartzite and clay-slate, in the direc- 

 tion of Bethelsdorp and Chatty. But, again, this of itself is no proof; 

 for near the Shark's River one of the most recent shell-deposits 

 also rests directly on the quartzite. 



Z>^^5. — We will therefore first enter into the question of dip, 

 especially that of the Government Saltpan — in the first place, how- 

 ever, premising that between this Pan and the saliferous deposits of 

 Bethelsdorp and the neighbourhood of Port Elizabeth the strata of 

 the Zwartkops, as shown in sections B & C intervene. The Pan 

 itself is in a denuded depression ; but this hollow is not very deep, 

 as is indicated by the rising ground that surrounds it, and from 

 the top of which a plateau stretches on the same level as the upper 

 edge of the Zwartkops Heights — in fact, is continuous with them, 

 as is seen at d' in Section R ffig, 7). 



Dr. Atherstone * says that the strata at Geelhoutboom dip S.W., 

 towards the centre of the ancient estuary, at an agle of 8°, and those 

 of the Zwartkops conversely N.E. ; and he gives the dip of the Salt- 

 pan rocks at the same angle to the north-east, that is, in the same 

 direction as those of the Zwartkops. Kow it is certain that for a 

 number of miles together the dip of the Zwartkops strata continues 

 with great uniformity at nearly the same angle. But an angle of 

 8° gives a depression of about 1 foot in 15 ; and if continued two 

 miles (about the distance of the Government Saltpan from the top 

 of the Zwartkops Heights), there would be a total fall of some 1500 

 feet. The highest hiUs anywhere in the neighbourhood are the 

 Koega Kopjes ; and they are only 480 feet above the level of the 

 sea. The depression of the Saltpan is certainly not 300 feet below 

 the level ef the Amsterdam Flats, the plateau from which these 

 Kopjes rise, as that would place it below the level of the sea, which 

 it decidedly is not ; but, even allowing it to be so, the angle given 

 would place the Zwartkops sandstones, if they extended as far as the 

 saliferous strata of the Saltpan (which I think is not doubted), 

 1200 feet below them. A dip of 4° (the same as at Eocke's Bluff) 

 would allow rather more than 700, or some 400 feet below : and 

 even the small angle of 2° would stiU leave the Trigonia-hedfi be- 

 tween 70 and 80 feet lower than the deposits of which I am 

 speaking. 



Fossils. — At the Government Saltpan (p. 505) Dr. Atherstone has 

 found Trigonice and Turritellce associated with Ostrece and Cidaris 

 pustulifera. I cannot help thinking that this is the oldest portion 

 of the saliferous strata that has been yet examined. The stratified 

 clays of the Bethelsdorp Pan and those at the Salt Vlei are, I be- 

 lieve, more recent. At the former of these Cidaris and Ostrea 

 are abundant ; but no Trigonim are yet known there ; while at the 

 latter spot no specimens of either the one or the other have been ob- 

 tained, although Cidaris has been found on the sides of the outlier 

 (Section 0, fig. 4) on the east of the Vlei. This outlier, I believe, 

 * Loc. cit. p. 581, and woodcut, no. 1. 



