Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/671

 of all these lies an irregular deposit of a sandy calcareous tufa, covered with a reddish sandy clay. The remarkably uniform thickness of the several clays and sandstones in these sections is worthy of notice.

From another Section, marked L (see fig. 6), that I was able to obtain in a higher bank about 300 or 400 yards to the N.N.E. of Section M 1, No. 14 does not appear to be the uppermost in this series. This higher section shows nearly the same dip as the lower one ; and in it we find a broad band of sandy clay (No. 11) 8 feet in thickness, interspersed with a great number of calcareous stripes near the top. Above this is 2 feet of clay (No. 10) of a pale-greyish stone- colour, (No. 9) six inches of a sandy yellow and brownish striped clay ; and above that, (No. 8) two feet more of the same clay as No. 10, with a superficial loam. In the foregoing sections, we therefore obtain (if the uppermost bands belong to the series) a combined thickness of more than 52 feet of these stratified clays. The latter section is capped with the same reddish sandy clay as the former ; and I have not been able to find in these two places any trace of a deposit that might be considered the equivalent of the Zwartkops and Koega Posttertiary shell-limestone.

The Salt Vlei near Port Elizabeth. — About five miles nearer to Port Elizabeth, in the clay-pits, at a place called Salt Vlei, we find another excellent section of the stratified clays. This is shown in Section N (fig. 6, 2). In these pits the lowest uncovered rock is that marked No. 18 in the section — namely, a marly, gritty sandstone. It is exposed for a depth of 14 feet ; the remainder of it (whatever the entire thickness may be) is covered up with the debris of the excavation. It appears, as far as can yet be seen, to be non-fossiliferous. Immediately above this is a belt of clay (No. 17), and on the clay a band of nodular concretions (No. 16) fourteen inches thick. These nodules are irregular in shape, and of various sizes, some of them being upwards of 2 feet in length ; when broken they all display the same fracture as that shown in specimen No. 16*, with a powdery nucleus as in specimen No. 16 a†. In situ, they lie as if they had been regularly packed, their greatest length being in the direction of the dip.

Above this noduliferous band is a sandy clay, No. 15, 2 feet thick, of a yellow-ochre colour. Upon this follows a dark slate- coloured clay, No. 14, also 2 feet thick. The strata Nos. 14, 12, and 10 are clays to all appearance exactly alike, as regards colour and texture, and must have been deposited under similar circumstances. No. 13, 1 foot thick, is the first zone (in this section) in which were found traces of fossils. It is full of small marine shells [Astarte (?) and Natica or Phasianella (?), T. R. J.] : some are very beautiful ; and all were so delicate in structure as to be very difficult to remove.

No. 12 is a clay, 3 feet thick ; then comes a single line of nodules, No. 11. These nodules are placed either singly or in groups, as shown in the section, all in the same line of bedding. No. 10 is


 * No. 16. Ferruginous sandy nodule, with ochreous centre.— T. R. J.

† No. 16a. Dark red-purple earthy haematite. — T. R. J.