42 THE CANGO CONGLOMERATES 



several varieties of conglomerate in the Cango beds, 

 differing chiefly in the nature of their contained pebbles 

 and iii, the amount of shearing they have undergone. In 

 the west, on the hills north of the Ladismith Road 

 near Vaartwell, the conglomerate has been sheared to 

 such an extent that the original forms of the pebbles 

 (slaty rocks and vein-quartz) are no longer recognisable, 

 and in many cases the exact limit between pebble and 

 matrix is indefinite. Farther east the conglomerates 

 are more normal in character, but the effects of shearing 

 are still very evident. In Schoeman's Poort, where 

 excellent sections through the conglomerate are exposed 

 by the roadside, large pebbles or boulders of granite and 

 diabase are seen in it. The occurrence of these is in- 

 teresting, as it proves the Cango beds to be later in 

 age than some rocks possibly the Malmesbury beds 

 which were invaded by granite and diabase before they 

 furnished sediments for the building up of the Cango 

 beds. So far as is known at present there is no uncon- 

 formity at the base of the conglomerates of which there 

 are at least two bands, and although in the Grobbelaar's 

 Valley, and other places farther west, slates are seen on 

 either side of the steeply inclined conglomerate, it is 

 even difficult to decide which is the top and which the 

 bottom of that rock. It may be that the bottom is 

 nowhere seen, and the slates on either flank of the 

 conglomerate overlie the latter. 



A remarkable group of beds, formed chiefly of various- 

 sized fragments of quartz and felspar, extends for a 

 considerable distance along the strike of the Cango 

 series, half a mile north of the conglomerate between 



