Page:The Geologist, volume 5.djvu/74

56 with the strata among which they lie. The claystone-porphyry of Bain, appears conformable as to individual beds, while in the mass it crosses the section of the country. I have never found igneous rocks in the positions of upheaving rocks. I have repeatedly found them in positions (4, 5) where they could not possibly be so. In Namaqualand the rocks between Springbok and Concordia were perhaps more decidedly gneiss-like than in any other part of the section, except perhaps near Kok Vontein, yet I regard these two spots (the former about a mile north of Springbok Vontein, the latter two miles south-east of Kok Vontein) as the main axial lines of the country. Many facts concur to prove that whatever may have been the cause of the upheaval of strata in this country, igneous rocks have had nothing to do with it. That there are considerable difficulties about the stratification of this neighbourhood, I fully believe. That I have no clue to the satisfactory explanation of those difficulties I am obliged to confess. To mention one or two, I believe that encrinites are generally local in their distribution, that is, individual species are confined to a few beds; and that if the same species of encrinite is found in these spots, the rocks containing them may be safely assigned to the same age or near it. At the northern base of the Coxcomb are some nearly horizontal beds of blue and ferruginous schists containing trilobites, shell-fish, and encrinites, pronounced Devonian on good authority. The strike of these rocks is north 60° west nearly, and this line of strike would pass through Cape Reciffe. The Chatty beds of shale, which are in hills continuous with those of Port Elizabeth, would nearly correspond in strike with these beds; and at Chatty two or three encrinites identical with those of Coxcomb occur. Yet at the former place the rocks dip at an angle of 45°. There do not seem to be any igneous rocks to account for this difference. At Naroos, near Uitenhage, the slaty beds are associated with quartzite, and dip at 60°–70°.

Again, the beds containing spirifers or this encrinite at Kabeljouw river's mouth, Jeffrey's Bay, have but a slight dip on the seashore; a little inland they have a greater dip, but at Hermansdorp, where the same spirifers or this of encrinite occur, they have a dip of 80° close to their junction with the quartzite. I cannot account for these things. I suppose no one in the present day would call quartzite an igneous or upheaving rock. Yet it is certainly my impression that if any rock in this country influences the change of dip in either rocks, quartzite does. Mr. Niven, the gentleman from whom I have the last fact, and who has done so much in throwing new light on the geology of this province, tells me that the quartzite, a hundred and eighty yards from the slate, dips 45°. If compelled to suggest a reason for these things, it would be, that whereas quartzite might be metamorphosed by addition of matter infiltrated, claystone, porphyry, granite, etc., might owe their origin to mere crystalline action under the agency of water, thermo-electric currents, etc. This last is Mr. Sterry Hunt's view, I think.