Page:The Geologist, volume 5.djvu/67

Rh from it. I believe his wide dislocation of the Ceres beds from the clay-slate to be an error into which he has been led by a state of things like that of Ezel's Poort. I have never been able to get direct proof that this is the case here, although I have elsewhere, as shall presently appear.

On my return to the Eastern Province, I thought I saw evidence of the siliceous change of rocks on a much greater scale than I had observed them in Namaqualand. T wrote a Paper on the subject, and published it in the local magazine I have quoted above ('Eastern Province Magazine,' vol. ii. p. 187). I hoped it would have led my friends here, from whose sections mine differed considerably, to re- examine their data. A little after, I sent home a Paper which was read at the Geological Society of London (see an abstract of it in the 'Geological Society's Journal,' vol. xv. p. 195), in which I explained these views, and predicted that the clay-slate of the west would hereafter be found identical with the Upper Silurian of Bain, and the Carboniferous rocks of the east identical with both, the quartzite being changed rock, sometimes slate itself, sometimes a newer unconformable rock. Of this identity I was enabled to send home strong presumptive proof in the shape of fossils identical with the Upper Silurian of Bain, from the clay-slate on the western shores of Francis Bay. More recently I have obtained the same fossils (pronounced Devonian at home) from various points between the Kromme and Kabeljouw rivers, St. Francis Bay, in the clay-slate, and from Chatty, near Port Elizabeth; from Naroo, near Uitenhage; from Blauw Krants, on the Bezuidenhouts river, on the road to Graaff Reinet; and from the northern base of the Coxcomb in the Winterhoek range in the Carboniferous. Still, it might be objected that there may really be a difference between the clay-slate and the Devonian, though Mr. Bain may have mistaken the line of division. If reference be made to the Admiralty chart of St. Francis Bay, it will be seen that the low shores of the bay are crossed by a range of mountains of considerable elevation. These mountains, which are quartzite, cross the strike at a considerable angle, nearly, in fact, for some distance at a right angle; so that on the beach and the low hills you may cross near ten miles of slate, perhaps five miles of strike, while six or eight miles inland, on the heights, the corresponding part of the section is all quartzite. The quartzite must, consequently, cross unconformably the slates, and therefore be newer than they. The reasons why they cannot be older, I need not give here, as I have given many of them above. These same quartzite hills are continuous with others of the same lithological character, which are decidedly conformable with the Devonian rocks, though they too cross the strike at an angle of 30°. I have not had opportunities for such an examination of the country between this and Cape Town, as to enable me to say positively that there are no beds older than the Devonian; but I think I have shown satisfactorily that the evidence on which the clay-slate is referred to a much higher antiquity is fallacious. I can safely assert that the Devonian beds of this country are crossed by lofty