Mr. D. Sharpe and Mr. Salter on Fossils from South Africa. 203 



Note. — The following shells are of minute size, and occur together in a hard 

 argillaceous limestone of a reddish colour, labelled " Snieuwberg? " by Mr. Bain, 

 but lately recognized (since the figures were drawn) as identical with a fragment, 

 marked " Lowest strata of the Zwartkop crag," in Dr. Atherston's collection. 

 The latter label has been adopted. This shelly rock contains also fragments of 

 wood and bone, and is probably of estuarine origin, as, with some fluviatile or 

 lacustrine shells, it contains a number of very minute marine mollusks, of genera 

 often found in brackish water : these may be dwarfish individuals of species which 

 would have reached a larger size in purely marine waters*. Believing this to be 

 the case, I have not ventured to compare them with any published species ; nor 

 do I think that any conclusions as to the age of the bed in which they occur can 

 safely be drawn from the shells themselves. — Daniel Sharpe. 



. Avicula Bainii, Sharpe. PI. XXVIII. fig. 10. . 

 Modiola Atherstoni, Sharpe. PI. XXVIII. fig. 11 

 Sanguinolaria? Africana, Sharpe. PI. XXVIII. fig. 12 

 Cyrena? Bainii, Sharpe. PI. XXVIII. fig. 13 . 

 Trochus Bainii, Sharpe. PI. XXVIII. fig. 14 . 

 Turbo Atherstoni, Sharpe. PI. XXVIII. figs. 15 & 16 



Bainii, Sharpe. PI. XXVIII. figs. 17 & 18 . 



Acteon Atherstoni, Sharpe. PI. XXVIII. fig. 19 . . 

 Natica Atherstoni, SAarjye. PI. XXVIII. fig. 22 . . 



■^ 



Lowest strata of the 

 Zwartkop crag. 



Description of Palceozoic Fossils from South Africa. 

 By Daniel Sharpe, Esq., F.R.S., Pres. G.S., and J. W. Salter, Esq., F.G.S. 



Introduction. 



The few South African fossils originally collected by Dr. Andrew Smith, in the 

 Cedarberg, and referred to in the " Silurian System," are identical with those 

 found by Mr. Bain more to the southward, in the Bokkeveld, and have been 

 illustrated together with the latter in the following pages. 



As we are unable to identify any of these South African fossils with species 

 which have been described from districts where the age of the formations has been 



* Since the above was written, some of the species of shells occurring in this rock have been found to 

 be represented by large individuals in the greenish-grey shelly grit of the Sunday River: see p. 201. — 

 Editor. 



