194 THE ECCA BEDS 



Natal, who include in the Ecca beds the strata that im- 

 mediately succeed the Dwyka tillite. 



Attention has already been drawn to the uncertainty 

 as to the exact geological horizon of these beds, and in 

 our present state of knowledge it would be useless to 

 discuss the question of correlation any further. Through- 

 out Cape Colony, hovvever (except near Rietfontein in 

 Gordonia), where the Karroo formation appears to have 

 been more fully developed than in the neighbouring 

 Colonies, the name Ecca series has for various reasons 

 been applied by the Geological Survey to the beds that 

 overlie the " White band " of the Dwyka series or the 

 highest chert band in that formation when beds of chert 

 are present. 



In the south and west of Cape Colony the lowest 

 Ecca beds are usually thin flaky blue shales, and green 

 shales are found above them, together with thin beds of 

 mottled grey and green sandstone. Some of the shales 

 near the base of the series break up into long roughly 

 prismatic fragments after the manner of the starch of 

 commerce. In the neighbourhood of Patata's River 

 south of the Klein Roggeveld hard sandy beds lie im- 

 mediately above the Dwyka series. The thickness of 

 the lower portion of the Ecca beds in the south and 

 west, in which the shales predominate, is from 1,000 

 to 1,200 feet, and they are succeeded by some 1,200 

 feet of strata in which sandstones are the chief feature. 

 These, called the Laingsburg beds from their occur- 

 rence near the town of that name, are hard, dark- 

 coloured, fine-grained sandstones and hard shales ; they 

 contain Glossopteris, fiohizonewra, Phyllotheca and silicified 



