Part I. § 2. Tertiary or Posttertiary Strata.
[Abridged*.]
1. Pliocene or Postpliocene Strata of the Interior. — Having thus noticed the older rocks, I will now proceed to make a few remarks on the so-called " Tertiary Limestone"†, which covers in many places the rocks we have been describing. This series caps the top of the Zwartkops Cliffs, extending from Rocke's Bluff (see Section R, fig. 7), along the top of the hills towards Uitenhage, and resting upon the Jurassic sandstones. The greatest accumulation appears to be on the Amsterdam Flats and the Grassridge. At the Koega it is found upon the friable non-fossiliferous sandstones of that locality (see above, p. 506). At the Sundays River it is seen on McLoughlin's Bluff as a narrow belt. These positions are shown in Sections E and R (see fig. 7). From the Zwartkops to the quartzite ridges of Port Elizabeth, I am not aware that any traces of it have been found. Mr. Pinchin, who has paid much attention to this formation, states (in a letter) that " it covers the upper part of the plain (Amsterdam Flats), extending westward to Hitzeroth's (the Old Government) Saltpan, and along the tops of the bills to within a mile of Uitenhage ; it covers the whole of the Grassridge
- The sections and sketches sent by
the Author for this portion of his Memoir are deposited with the others in the Society's Archives ; and the large collection of recent and fossil shells &c. sent by Mr. Stow, in illustration of his views as given in this paper, awaits examination by Mr. W. S. Dallas, who kindly promises a full report. — T. R. J.
† This is the limestone termed " Tertiary " in Mr. Bain's Geological Map of the Cape Colony, Geol. Trans. 2 ser. vol. vii. pl. 20. — T. R. J.
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Fig. 7.-Section showing the relative positions of the Trigonia-beds, the Saliferous group, and Posttertiary Shell-Limestone. Section R of Author.) Length about 25 miles.
a, a. Zwartkops-and Sundays-River Sandstones. b. Saliferous beds. c. Soft friable Sandstone. d, d'. Posttertiary Shell-beds.
