76 E. H. L. SCHWARZ 
me, because the fossils are extremely rare and localized, whereas the 
formation can be very clearly recognized by its lithological char- 
acters. Where the usual fine-grained blue sandstones of the Beau- 
fort Beds proper give place to the coarser-grained white varieties, 
one can at once draw a line of division and map the latter as 
Idutywa Beds. The Idutywa Beds extend into the Western 
Karroo north of Laingsburg and far to the north in the Transvaal. 
SEDIMENTARY CAP 
DOLERITE 
3S a 
: Sint 
'“ KRANTZES 
Fic. 5.—Western end of the Quizzyhota laccolite, showing the vertical face of the 
laccolite on the north and the sedimentary beds, plastered, as it were, onto the face» 
themselves quite undisturbed. 
They once had a wider area of deposition than any other of the 
divisions of Karroo System. 
Toward the middle of the descent of the Kei Hills the white 
sandstones disappear, and in their place there are the ordinary 
blue and blue-black shales, weathering olive-brown, which belong 
to the Beaufort Series. The normal sandstone banks of the forma- 
tion farther west do not appear, probably because the weathering 
is so different. Here in the east, the country is a recently dissected 
plateau covered with grass and scored by deep ravines; in the west 
