1. Left valve, dorsal aspect; 1a, umbonal region of the same
valve, 2. Three hundred yards below Addo Drift (Tunbridge's),
left bank of Sunday's River (41h).
2. Right valve; 2a, dorsal aspect; 2b, frontal aspect. Same
locality (40h).
3. Interior of a right valve. Same locality (42h).
4. Right valve; 4a, frontal view; 4b, dorsal aspect of the umbonal
region of right valve and fragment of left valve, showing details
of sculpture. Above Modder Drift, Sunday's River. In the col-
lection of the Geological Society of London (No. 12006).
5. Left valve. From the South African Museum collection;
probably Sunday's River.