TERTIARY AND RECENT DEPOSITS 411 



10. PANS. 



Of great interest are the peculiar depressions to which 

 the name of "Pans" has been given. There are two 

 classes of these ; the first consists of the pans near the 

 coast, the second of those lying far inland. 



The pans on the coast are usually at a low level, 

 separated from the sea by a belt of sand dunes. There 

 are several of these on the west coast south of the Oli- 

 f ant's Kiver. Rain-water collects in them, and owing to 

 there being sufficient clayey matter or limestone round 

 them the water does not drain away but evaporates 

 slowly, leaving a thin crust of salts, mostly composed of 

 sodium chloride or common salt. Usually the thin 

 crust is not sufficiently free from sand to be used for 

 domestic purposes, so shallow trenches are dug in the 

 floors of the pans during the dry season and a deposit 

 of salt three or four inches thick is formed in them 

 after the rains. The salt is probably collected by the 

 rain-water in its course through the surrounding sandy 

 soil, which receives it gradually from the sea in the 

 form of spray or attached to the grains of sand blown 

 from the shore. 



On the coast of Bredasdorp there are several produc- 

 tive pans. Some of them are within a short distance 

 of pans which contain fresh or nearly fresh water only, 

 yet no difference in the conditions of the salt and fresh 

 vleis is observable. This fact is difficult to explain on 

 the supposition that the salt is washed into the pans 

 from the surrounding soil ; but at no distant period the 

 low-lying parts of the Bredasdorp coast must have been 



