Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/659

 Herzogii are rather frequent. The other shells are Gervillia dentata, Pholadomya dominicalis, Exogyra imbricata, Area Jonesii, and an Ostrea. In the bed, marked No. 12, near the upper part of the bluff (figs. 1 & 3) we find Exogyra imbricata very abundant ; Astarte Herzogii and Pleuromya lutraria are numerous ; but of Astarte Longlandsiana only one specimen has been found, and one of Trigonia Cassiope. The other fossils known to occur, in bed No. 13, are : — Area Jonesii, Cucullcea Kraussii, Pinna Atherstonei, Placunopsis subjurensis, Trigonia ventricosa, T. conocardiformis, Ostrea, Pecten?, Ammonites. No. 13 is about 50 feet above the level of the river, and No. 12 about 200 feet. The rocks in this section dip 2°-4° from the river in- wards, and are surmounted by Pliocene (?) limestone.

Upper* Zwartkops River. Section on the Old Road. — Some miles further up the river, on the old Grahamstown Road (fig. 1), above the drift (ford), another fossiliferous bed (No. 11 ) is exposed along the hillside and across the road, as shown in Section B (fig. 3), some hundred feet above the river. The dip of the strata here, said by Dr. Atherstone to be about 8°, is inwards from the banks of the river. It is here that Cuculloea Kraussii is found more frequently than in any other of the fossiliferous bands, together with Trigonia Herzogii, Astarte Herzogii, and Pleuromya lutraria, all of which are very numerous, and may be looked upon as the characteristic shells of this stratum. The Cuculloea, especially, seems to have flourished at the time of the formation of this bed, and must have grown to a large size, as its fragments show. The other fossils are : — Pleuromya lutraria, Ceromya papyracea, Trigonia Herzogii, var., T. conocardiformis, T. vau, Exogyra imbricata, Pecten, Pinna, Patella.

Section at Cuyler Manor. — Still further up the stream, near Cuyler Manor (fig. 1), is another exposed portion of this formation. I have not visited this locality myself ; but Mr. Longlands, who examined it in 1867, very kindly furnished me with the section shown in Section C (fig. 3).

In the stratum of friable sandstone, marked 10, he found Ammonites, and very numerous specimens of Trigonia Herzogii ; in fact the latter abounds so much that it may be looked upon as the most characteristic fossil of this section. He also found a few specimens of Exogyra imbricata, and a few fragments of Trigonia conocardiformis and Pleuromya lutraria.

Remarks. — As the whole of the Zwartkops strata dip inland, and along the course of the river, which has a somewhat rapid fall towards the sea, I think these circumstances tend to prove that these fossiliferous bands, as shown in Sections A, B, & C (fig. 3), are not one and the same stratum, but form aparallel series, as is shown (in an exaggerated form) in fig. 1. Thus the stratum No. 13, in which Astarte Bronnii abounds, must be the lowest ; the bed, No. 12 at Rocke's Bluff follows, with its multitudes of Exogyra; the Cuculloea- bed on the old Grahamstown road is the next in succession; and,

Rivers does not indicate the highest parts of those rivers, but some portions towards the furthermost range of the Trigonia-beds traversed by them. — T. R. J.
 * The word "upper" here used in reference to the Zwartkops and Sundays

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