TERTIARY AND RECENT DEPOSITS 389 



Orange is very slight compared with that of the rivers 

 south of the main watershed ; their valleys are more 

 open, and towards their lower ends tend to disappear in 

 the "vloers," the flat alluvial ground quickly flooded 

 during storms but baked hard and drab a few hours 

 later, that are a characteristic feature of the arid country 

 south of the great river. 



In the Western Karroo the rivers draining the Rog- 

 geveld escarpment receive a sudden check on leaving 

 the Karroo formation and entering the region of the 

 Witteberg beds, which are of a harder consistency. In 

 the Bosch Kiver Valley on Witte Vlakte a well has 

 been sunk 140 feet through alluvium without reaching 

 solid rock ; this river has deserted its former channel, 

 now marked by a very conspicuous poort in the beds 

 west of the Poortje pan, and has turned southwards to 

 enter the Draai Kraal's Kiver several miles from its 

 former point of junction. 



The rivers of the west coast, from the Great Berg to 

 the Olifant's, have considerable tracts of alluvium along 

 the lower forty miles or so of their valleys. The Berg 

 Kiver alluvium extends to a depth considerably below 

 sea level at many spots where wells give information 

 bearing on the question. 



Very little is known of the fossil contents of these 

 river deposits, many of which are of quite recent origin, 

 and therefore probably contain only the remains of 

 living or lately extinct animals. The imperfect head of 

 a gigantic buffalo, 1 Bubalus baini (Seeley), measuring 

 eight feet six and a half inches between the horn-tips, 



1 Seeley, G. M., 1891, p. 199, 



