304 THE MOSSEL BAY OUTLIER 



of a bed of marine fossils between the red gravels and 

 sandstones north-west of Uitenhage, proves that the 

 sea at one time invaded the non -marine area, and the 

 Trigonia of the Pisang Eiver beds points in the same 

 direction. The Trigonia of Pisang Eiver proves also 

 that these rocks were formed at about the same time 

 as the Sunday's Kiver beds. 



Still farther west, in the divisions of Mossel Bay, 

 Kiver sdale, Eobertson, Swellendam and Worcester there 

 are large areas of conglomerates, sandstones, shales and 

 mudstones, resembling to some extent the Enon beds 

 but containing some varieties of sediments not met with 

 in the Uitenhage Division ; and again in the country 

 between the Langebergen and the Zwartebergen, in 

 the divisions of Willowmore, Uniondale and Oudt- 

 shoorn, there are large areas of similar rocks that in 

 spite of the absence of fossils must be relegated to the 

 Uitenhage beds. 



All these masses of rock occur in a more or less 

 similar manner ; they occupy basins partly cut out of 

 the older rocks, but in part due to earth-movements 

 subsequent to the Uitenhage period. They extend far 

 below the present level of the rivers traversing them, 

 and are generally elongated in an east and west direc- 

 tion, roughly parallel to the strike of the older rocks. 



The Mossel Bay area is perhaps the most interesting 

 of these patches of Uitenhage beds, for it has yielded 

 several fossils that can be compared with those of the 

 Uitenhage district. It is rather irregular in shape, 

 about fifty miles long from east to west, and at the 

 most fifteen miles wide. The northern boundary is 



