8X0W SOTTTH-APBICAN GEOLOGY. 



519 



a Tapes ; these shells are perfect ; but, although they are so numerous, 

 many of the shells found in the banks at the creek and Ferreira's 

 Eiver are wanting. It is worth considering whether or not this in- 

 dicates a series of these deposits. All the shells in the lowest part 

 of the stratum at this spot have both yalves perfect, some of the 

 Mactrce still retaining a portion of their colour ; those imbedded in 

 the limestone, nearer the surface, are in a more fragmentary con- 

 dition. 



The section I have called " the raised-beach " is, as above stated, 

 some 40 or 50 feet above the level of the sea; but unfortunately the 

 upper portion is the only part sufficiently exposed for examination. 

 From the indications on the beach below, it most probably rests on 

 a sandstone there shown. Almost every shell in the remains of 

 this ancient beach is broken, in the same manner as those now 

 found on the present sea-shore where exposed to the full action of 

 the waves rolling in from the ocean. 



At the creek on the Grahamstown Koad this deposit has been 

 cut through for some 12 feet in depth. Here, again, most of the shells 

 are perfect, and do not seem to have been exposed to the action 

 of rough water. This is eminently the case with the contents of the 

 shell-bank further up Ferreira's Eiver, and near Cradocktown. At 

 this place the deposit rests upon a bank of drift, with bands of large 

 angular pieces of quartzite ; this drift overlies a loose gritty sand- 

 stone. In the drift there are scarcely any indications of fossils ; but 

 in the deposit above there are strata of innumerable shells in a sandy 

 calcareous matrix. This sheU-bed, capped with a red clay, several 

 feet thick, is the most prolific portion of the deposit we are now 

 treating of. The shells are aU perfect, with the most delicate orna- 

 ments preserved. 



With the exception of a Psammohia, none of the shells found here 

 have, up to the present time, been found on the shores of the bay. 

 Still, in the whole series of shells collected, there is a nearer ap- 

 proach to those of the present ocean, while there is a marked 

 difference in character between these fossUs and those obtained from 

 the ^Z;era- stratum. 



These shell-deposits at Ferreira's Eiver &c., must have been laid 

 down in the waters of a bay, stretching from the Zwartkops to the 

 Port-Elizabeth hiUs, and extending some miles inland. On the in- 

 tervening ridges no signs of them are to be traced. In fact, it 

 seems almost certain that the ridges must have stood out of the 

 surrounding waters as islands. This is remarkably the case at the 

 creek, where the high ridges alluded to will be seen. "When stand- 

 ing on the shell-bank at Ferreira's Eiver, one cannot help being 

 strongly impressed with this idea, and that the sea must have 

 been as calm there as iu a land-locked bay, protected as it evidently 

 was from the roll of the open ocean. The appearance of the 

 sheUs themselves strengthens this view of the case, from the 

 beautifully perfect state in which almost all of them are found — 

 * with all their most delicate outlines j)reserved, and the bivalves 

 almost invariably having both valves uninjured and closed. These 



