228 i\ H. HATCH. 



The phosphate nodules occur both as isolated bodies in the 

 shales and as portions of nodular layers. A considerable 

 amount of phosphatic material is also found in the form of 

 hard seams, in which no nodular structure is developed. In 

 this case the tri-calcium phosphate appears to have been 

 removed in solution from the original skeletal remains which 

 contained it, and distributed more or less uniformly over 

 considerable areas. This explains why the phosphatic seams 

 (''reefs") are found to be poorer in phosphate than the 

 nodules. 



The beds in which the phosphates occur are the well-known 

 black, fine-grained, laminated shales of the Ecca Series, and 

 the loose fragmentary material into which the shales Aveather 

 forms a very characteristic and rather sterile-looking land- 

 scape. In Natal the Ecca Shales, which overlie the Dwyka 

 conglomerate conformably, are of great thickness (about 

 1000 feet near Pietermaritzburg) . The horizon on which 

 the phosphates occur is near the top of the series, i.e. a 

 little below the point where the shales commence to pass 

 into the arenaceous beds ("Ecca Sandstone"), which carry 

 the coal measures of Natal. ^ 



' I follow Anderson in classifying the Natal coal measures as Ecca 

 rather than as Beaufort. There is complete conformity from the Ecca 

 to the Beaufort, and it is immaterial whether the division between the 

 Ecca and the Beaufort be drawn alcove or below the coal measures. 



