Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/674

 too thickly covered with soil &c. to obtain a trustworthy section ; nor can I, of course, say whether its strata assimilate rather to the clays and sandstones of the Bethelsdorp Saltpan ; but Dr. Rubidge told me that he picked up a number of the spines and plates of Cidaris pustulifera among the debris of this outlier. All I can speak of with certainty is from Section P (fig. 5), which I was able to make during the excavation of a large tank on the top of this outlier. In this section the surface-soil was interspersed with shingle (as in Section N). Below this was a band of tufa, from 12 to 18 inches in depth ; then 2 feet of friable sandstone, interspersed with carbonate of lime, as shown in the section ; again tufaceous limestone, from 5 to 7 inches ; beneath that, 13 inches of sandstone, interspersed with carbonate of lime in the same manner as the sandstone above ; again 1 foot of limestone, then sandstone 3 feet; below this, three uneven belts of sandy limestone and sandstone, respectively 6, 7, & 6 inches thick ; these were followed by 1 foot of sandstone, of the same character as the thick band above ; and beneath them all, at the bottom of the excavation, was a reddish sandstone, the thickness of which is at present unknown.

Very little is accurately known of the fossil contents of the strata shown in the last three sections. They evidently require attentive examination, and promise a rich harvest to future explorers. Since my departure from Port Elizabeth, Messrs. Kemsley & Burness have found fossil Ferns in some of these clays, but have not been able to identify them with any of those from Geelhoutboom, on the Sundays River*. The clay in which they were found " rested upon sandstone containing immense fragments of leaflets and petioles of Zamioe, mixed with pieces of wood." To this discovery I shall have to allude again (p. 513).

Resume of the Strata of the Saliferous Group. — None of these sandstones that I have examined possess the close, compact nature of those found among the rocks of the Lower Zwartkops in Section A (fig. 3) ; but they are all of a coarse gritty texture, very like those I have spoken of as being found on the Koega (p. 506).

In looking over the various sections of these stratified clays and saliferous sandstones (namely I — P), one cannot help being impressed with their diversified aspect, each section differing widely from the others ; and they seem to indicate that we are not examining a single wide-spread deposit, but a partially consecutive series, something similar to, but of more limited extent than, those of the Uitenhage formation before considered. This becomes more apparent by looking at the diagram (fig. 6), in which the foregoing sections are collated and compared.

Here the section near the Salt Vlei, noticed by Messrs. Kemsley and Burness (fig. 6, 3), becomes an important addition, as by it we find that Trigonioe, Turritelloe and a Gervillia were obtained from the lowest stratum of sandstone in this formation, while the clays with Ostrea and Tellina (?) are above. This sandstone deposit appears to be one of the oldest, if not the most ancient, of this Saliferous formation.


 * Quart. Journ. Geol. Soc. vol. xxiii. p. 145 &c.