312 THE SWELLENDAM AREA 



bottom of the hole the bore passed through a boulder 

 of micaceous slate seven feet in diameter. There are but 

 few exposures of these beds, but the railway cuttings 

 east of the village show that there are sandy clays inter- 

 bedded with the conglomerates. 



The Swellendam beds have generally a low, north- 

 easterly dip, and the basin-shaped area occupied by 

 them must in part be due to earth-movements subse- 

 quent to their formation. 



Two outcrops of red sandstone and conglomerate 

 occur in the bed of the Groot Vader's Bosch Stream 

 and on the hill just south of it, where the main road 

 leaves the valley ; these outliers are situated between 

 the Swellendam and Heidelberg basins and point to the 

 former connection of the beds filling them ; a careful 

 examination of the district, with particular attention 

 to all excavations and cuttings that may be made, will 

 certainly prove the greater extension of the Uitenhage 

 beds in this area. 



In the country south of the Zwartebergen the gravels 

 and other deposits belonging to a comparatively recent 

 period often hide the underlying rocks, and in some 

 cases the gravels may be mistaken for the Uitenhage 

 conglomerates. With the high level gravels there are 

 often associated compact rocks whose grains are ce- 

 mented together by silica, carbonate of lime, or fer- 

 ruginous matter, and when once a person is well ac- 

 quainted with these somewhat peculiar rocks he can 

 readily recognise them in even very small fragments ; 

 their presence in a gravel at once distinguishes it from 

 the Uitenhage conglomerates. The high level gravejs 



