520 PEOCEEBINGS OF THE eEOLOGICAL SOCIETY. 



indications must surely prove that here they must have been de- 

 posited in still water, below or beyond the influence of the tidal 

 and other waves ; while, on the other hand, the shells of the 

 "raised beach" appear to have been deposited on a kind of 

 outer reef, exposed to the full force and constant action of the 

 sea, which broke them into fragments, and rounded oif their fractured 

 edges. 



§ 4. The Red Clay. — The deposit which seems to follow these 

 is the red clay, as shown at g g, in Section (fig. 4). The exact 

 position of this clay, to which I have before alluded (p. 518), 

 requires more careful examination than has yet been given to it. 

 There appears to be little doubt, from the section just referred to, 

 that it must be more recent than the shell-deposits we have been 

 describing ; for upon the flat, at a little distance from the north end 

 of Port EHzabeth, they are found cropping up through it. These 

 shell-beds, judging from their fossils, are identical with those of 

 Ferreira's River. However, as I have said, little is at present known 

 of this clay, except that it varies considerably in thickness in different 

 localities: thus it may form merely a superficial covering to the shell- 

 banks mentioned ; while the late Dr. Rubidge informed me that at the 

 New Prison it is some 60 or 80 feet thick ; and, at OKphants Hoek, 

 Dr. Atherstone states it to be 100 feet. "Whatever may be its thick- 

 ness, it must have been deposited under totally different circum- 

 stances from any thing preceding it. The transition from the one to 

 the other is so sudden that, with the hmited information we have 

 about it, it will have to be left to future investigation before its 

 history can be written, as well as to discover (what is probably the 

 case) deposits on other parts of the coast that may intervene be- 

 tween the sheU-banks and the clay, and others between the clay 

 and the formation which foUows, thus more clearly explaining the 

 changes that led to its deposition. 



§ 5. Latest SJiell-beds. — The next known deposit of the ancient 

 sea is that marked C, C, in section T 'No. 1, and C in T No. 2. This 

 is evidently the most recent, previous to the existing order of things. 

 In the Bight, as shown in the section, it is found in detached mounds 

 of drift-sand, with a thick horizontal bed of shells on the top. These, 

 however, from their position and structure, are merely the isolated 

 remains of what, at one time, was a continuous and wide-spread de- 

 posit. It is found on different parts of the coast, and is especially 

 remarkable on the south side of Port Elizabeth, towards a small in- 

 dentation caUed the Shark's-Eiver Mouth. In this locality the quart- 

 zite rocks (near the top of the ridge, and at an elevation of 180 feet 

 above the sea) have been worn away to a long slope by the action of 

 the waves &c. About one-third up the ascent, and resting upon the 

 quartzite, is a mass of conglomerate composed almost entirely of 

 quartzite fragments imbedded in hmestone, with fragments of shells. 

 There is another accumulation of conglomerate at the same place, at 

 a lower level, composed of waterworn pebbles. These conglome- 

 rates have been found at other parts of the coast. Upon this con- 

 glomerate, or, where it is wanting, upon the quartzite itself, are 



