194 Mr. D. Sharpe on Secondary Fossils from South Africa. 



valves of moderate thickness. Hinge-area of moderate depth ; ligamental hollows 

 broader than the spaces between them. 



Length 2 inches ; breadth 1^ inch ; thickness ^ inch. 



Found at Geelhoutboom, in greenish grit with fragmentary shells. 



An inconspicuous shell, with no marked characters, which it would be difficult 

 to distinguish from several European species. 



Fig. 4, left valve ; fig. 4 a, interior of right valve of another specimen ; fig. 4 b, 

 anterior side of fig. 4. 



Trigonia Vau, Sharpe. PI. XXII. fig. 5. 



T. testa ovato-trigona, inflata, tuberculato-costata : latere antico brevi, rotundato ; latere 

 posteriori producto : costis obliquis subtuberculatis, anterioribus retrorsum, posterioribus 

 antrorsum inclinatis, medio angulatis : area magna, declivi, bi-excavata, transversim lineata. 



Shell ovato-triangular, short and rounded anteriorly, produced posteriorly: 

 umbones projecting, very near the anterior extremity : area broad, divided in two 

 parts by a slight longitudinal ridge, and crossed by faint lines of growth : sides 

 ornamented with slightly tuberculated ribs, which form an angle of 70° to 90° on 

 the middle of the side of the valve ; the anterior ribs, small and numerous, slope 

 diagonally backwards ; the posterior ribs, strong and about ten in number, slope 

 diagonally forwards ; the meeting of these ribs resembles the form of the tetter V, 

 as in the genus Goniomya. 



Length 2 inches ; depth \^ inch. 



Found at Sunday River, in greenish-grey grit, with fragments of wood and 

 shells ; and in a shelly grit at the Zwartkop River. 



Pholadomya Dominicalis, Sharpe. PI. XXII. fig. 6. 



P. testa tenuissima, transversim ovata, costata : latere antico brevi, sublsevi ; posteriori 

 elongato, subrecurvo : umbonibus anticis, incurvis : area cardinali angusta, inconspicua : 

 costis 10 retrorsum vergentibus, prima remotiuscula, reliquis subeequidistantibus : rugis con- 

 centricis inconspicuis. 



Shell very thin, transversely ovate; anterior end very short and nearly closed ; 

 posterior end produced, with the lower margin rounded off and the upper side 

 slightly recurved, and moderately gaping: umbos forward and incurved : cardinal 

 area narrow and ill-defined : ribs ten, radiating from the umbo and sloping back- 

 ward ; the first widely separated from the rest, which are nearer together and 

 nearly at equal distances from one another. 



Length 1^ inch ; breadth 2^ inches ; thickness 1 inch. 



Found at Sunday River, in greenish grit. 



This shell is nearly related to P. Hausmanni, Goldf., of the Lias of Hanover, 

 from which it may be distinguished by having only one rib (instead of two) more 



