196 THE ECCA BEDS 



Between the Hantam and Van Wyk's Vlei nothing 

 is known about the Ecca beds, but the formation from 

 the latter point onwards is markedly argillaceous, and 

 as far as the Orange Hiver it forms a wide belt showing 

 great lithological uniformity. Sandstones are prac- 

 tically unrepresented, and the beds are almost entirely 

 bluish and greenish shales, which, towards the summit 

 of the formation, become rather flaggy. Calcareous 

 concretions are very abundant, more especially in the 

 middle portion of the series. No recognisable plant re- 

 mains have been obtained in this northern area, though 

 the shales are frequently crowded with indistinct fucoid- 

 like markings. Silicified wood is present, but it is not 

 abundant. The strata along the north of the Karroo 

 have a constant though very low dip towards the south, 

 and the formation must have a thickness of about 2,500 

 feet. A small outlier of Ecca beds builds up Kols Kop 

 a little to the north of Belmont. 



In Willowmore the normal phase of the southern 

 Ecca is replaced by shales and sandstones exhibiting a 

 white spotting or mottling on a blue or greenish-grey 

 background. They contain a large amount of silicified 

 wood, and some limestone ; the latter is penetrated by 

 thin veins of chert. The area occupied by this " mottled 

 Ecca " is as yet unknown. 



In Pondoland the Umsikaba beds occur just above the 

 black shales of the Dwyka series. They are of consid- 

 erable but unknown thickness, and differ in character 

 from the typical Ecca beds of the west ; they consist 

 more of clays and mudstones than of shales and sand- 

 stones. Near their base, as seen on the road to Lusi- 



