Page:South African Geology - Schwarz - 1912.djvu/169

 Conglomerate, in Australia the Bacchus Marsh Conglomerate, and in South America the Orleans conglomerate. The Karroo reptiles are only known from the Cape, India, and Russia; Glossopteris, however, all over Gondwanaland.

The Idutywa (Burghersdorp) Series, — In the reports of the Geological Survey these beds were described in 1901 as Idutywa Beds, and were again described, in 1905,

as Burghersdorp Beds. The series lithologically consists of white or buff sandstones, fairly loose-grained, separated by shales brightly coloured in blue or purple-red, often, however, grey, green, and mottled. The beds occur capping the highest hills of the western Karroo, and are found again in Aliwal North and the Free State, and again in Catheart, and in the Transkei, from Idutywa eastwards.

Glossopteris still occurs as a fossil in those beds, but they form a transition series between the Karroo proper and the Stormberg Formations, and therefore contain many of the Stormberg plants. The sandstones are full of freshwater fish, Semionotus, Cleithrolepis, Atherstonia, and Ceratodus, the Australian mud fish, which