The Volcanic Fissure under Zuurberq. 191 



beds themselves or of the older strata against which they lie, along 

 the fault lines in Willowmore and Uniondale, but this shattering 

 seems to be greatly in excess of what one would expect along faults 

 of no very great throw. 



Along the fault south of Zuurberg there are not only breccias 

 somewhat similar to those of Uniondale and Willowmore, but a most 

 remarkable band of lavas, accompanied by breccias of a more peculiar 

 type than those mentioned above. 



The country I am now dealing with is not a favourable one for 

 geological observations ; it is well covered with bush, which is in 

 places quite impenetrable, and the rich development of soil hides 

 the underlying rock over wide areas. The stream beds, too, although 

 they lie in almost precipitous valleys and have very steep grades, are 

 usually choked with a mixture of soil, fallen rock fragments, and 

 vegetation. The following description is therefore necessarily 

 incomplete, and may be somewhat modified by future work. 



Travelling along the road from Coerney Station to Zuurberg Pass, 

 after crossing the waterless Coerney Eiver, one sees occasional road- 

 side quarries in coloured marls, which dip south at 25° at one place, 

 and near the lower end of the long hill in the valley trending south- 

 east there are artificial exposures of the red Enon conglomerate 

 dipping south at about 35°. The road lies about W.N.W., but the 

 trend of the rocks is nearly east and west, and after an interval of 

 some hundred yards the rock exposed in the ditch by the roadside is 

 a highly vesicular lava, dull red outside and reddish-black within. 

 In the bottom of the valley at this place a well has been dug, and 

 most of the material thrown out is a heavy, dark, almost black,, 

 rather soft igneous rock, with many amygdales of some black sub- 

 stance. Near the surface the rock has a similar appearance to that 

 seen along the roadside, and the apparent difference between the 

 two rocks is probably due to weathering. As I have not yet had the 

 opportunity of making a close examination of the lavas and other 

 rocks of this fissure, I shall not go into the question of their peno- 

 logical nature. Proceeding up the road the next outcrop is seen in 

 the ditch about 400 yards above the well, and there we have greatly 

 disturbed thin shales and limestones, belonging to the Upper Dwyka 

 shales, and a few yards further on there is a road quarry in typical 

 Upper Dwyka shales, which are here also highly disturbed ; there 

 follows the usual downward succession through the Dwyka con- 

 glomerate, Lower Dwyka shales, and the Witteberg formation (see 

 Fig. 1). I could not get a close estimate of the width of the dyke- 

 like body of amygdaloidal lava, but it is not more than 100 yards 

 wide. From the well to the top of the ridge south of the road, but 



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