48 



THE GEOLOGIST. 



a line of eight miles tlirough G-raham's Town and near Salem, at right- 

 angles to this direction, it will pass through little but quartzite. If 

 we draw a line of the sarme length through the Commadagga beyond 

 the Zeurberg, it will pass through nothing but slates, Ecca rock, and 

 claystone porphyry. 



8. On the road to Graaff Eeinet is a place called Wolye Krool. 

 It is a plain, bounded by quartzite hills. Its section is this : — 



Here the Ecca rock contains Fig. 1. 



its characteristic fossils, is con- 

 formable with the quartzite. and ^ » Ifj 

 is separated from the Dicyno-,>A\ l|Pf9^\>( 

 don rocks by a nigmsa moun- 

 tain of quartzite and many miles ^ ^ ^ © h 

 of slate, porphyry, etc. I could 1 . J' 2 "I • 

 add many other reasons for this i I ^ 1 11 ^ 

 belief, but I think these will be ^ ^ ^- ^ ^ ^ 

 sufficient. AYhat is then the true relation of the quartzite to the 

 Ecca rock and the slates ? and how is it that at one part of a line of 

 strike the rock will be all of a blue slaty fossiliferous character, and 

 at another all crystalline quartzite, destitute, or nearly so, of fossils ? 

 How is it that in deep sections, natural as well as artificial, such as 

 are made by cutting roads or by deep gullies, the slaty rocks are found 

 below gradually passing upwards into quartzite ? Of this I could 

 give scores of instances, but I will select only one natural one. The 

 range of quartzite on the left-hand of the section is crossed by a bye- 

 road. This road passes for a mile or more oyer well-marked Ecca 

 rock, with the high quartzite hills on either hand. The quartzite on 

 the right-hand dies out, and the road to Graaff Eeinet passes over 

 Ecca rock in the corresponding part of the section. 



I found what I belieye to be the key to the explanation of these 

 facts in jSTamaqualand. In passing through Ezel's Poort, between 

 Springbok Yontein and Spectakel, I was shown a section which had 

 been noted by Dr. Atherstone as remarkable. The gneiss hills were 

 covered by horizontal layers of quartzose sandstone, and these were 

 continuous on the western side of the hill with like quartzose sand- 

 stone dipping at a In'gh angle westward, conformably with the gneiss. 

 It was clear that this change of dip was not due to any upheaval, for 

 the horizontal sandstones were found undisturbed a few yards distant. 

 I soon learnt to regard this juxtaposition of horizontal and inclined 

 beds, this continuity of quartzite conformable and unconformable with 

 its subjacent rock, as a normal state of things in Xamaqualand. AVhen 

 I saw high mountains with like structure, I was at first a little stag- 

 gered, but soon felt convinced that even on this scale the phenomenon 

 was due to the assimilation to each other by a process, common to 

 both, of rocks of widely different ages. 



In the Western Proyince I made, in a rapid journey from Cape 

 Town to Ceres, a selection from the clay-slate to the Upper Silurian 

 of Bain. I liad reason, as far as I was able, to confirm the truth of 

 Mr. Bain's section, while difierino: from him in the inference I drew 



