Notices of Memoirs — Pajiers read at British Association. 37 



coal-seams. Arenaceous material is predominant, and the sandstones 

 vary from fine-grained grey felspathic varieties to coarsely crystalline 

 ' glittering ' sandstones, with small pebbles of vein-quartz. Boulders 

 of hard white or brownish quartzite, derived evidently from the 

 Cape Formation, are common, usually scattered irregularly throughout 

 the sandstone beds, but occasionally forming conglomerate bands. 

 The coals are thin, and contain from 15 to 30 per cent, of ash, but are 

 the only workable deposits in the Cape Colony. Fossils are almost 

 entirely those of plants, e.g., Thinnfeldia, Taniopteris, Callipteridium, 

 etc., from which the Rhaetic age of the beds has been deduced. 



The Eed Beds are more argillaceous in character, and consist 

 of 600 - 1600 feet of strata, in which red and purple shales, 

 mudstones, and sandstones are predominant, though thick beds of 

 fine-grained white sandstone are also common. Fossil remains are 

 chiefly those of carnivorous Dinosaurs, such as Euskelesaurus and 

 Massospondylus. 



The Cave Sandstone is a thick bed of fine-grained felspathic 

 sandstone, usually white or yellowish in colour, and of very striking 

 appearance. As a rule, it is unbedded throughout, except towards 

 its summit, or less commonly towards its base. In some places it 

 attains a thickness of 800 feet, but as a rule it varies from 150 to 

 350 feet. In a few places the Cave Sandstone is entirely absent, and 

 the volcanic beds rest directly upon the red beds. The Cave 

 Sandstone weathers into most fantastic outlines, and gives rise to very 

 peculiar scenery along the Drakensberg. 



The sediments of the Karroo System were deposited in a great 

 inland sea, ' the Karroo Lake,' in which the water was either fresh 

 or slightly brackish, and not very deep. During the formation of 

 the Stormberg rocks the shore-line stretched where the coast ranges 

 of the south of the Colony now rise, and extended eastwards into the 

 Indian Ocean, and then north-eastwards parallel to the coastline of 

 Natal. This old land surface was formed of rocks belonging to the 

 Cape and Pre-Cape Systems, quartzites, granites, and metamorphic 

 xocks. 



During Cave Sandstone times volcanoes came into existence, and 

 great eruptions of basic lavas took place. Over 100 volcanic necks 

 have been mapped by the Geological Survey, some of which are 

 over a mile in diameter. Many of the pipes are filled with siliceous 

 breccias, or with fine-grained sandstone-like tuifs. The erupted 

 material consists almost entirely of basic lavas, compact to vesicular, 

 the most interesting variety of the latter being the 'pipe-amygdaloid'; 

 enstatite-andesites occnr in a few places. Beds of volcanic ash are 

 met with in Barkly East and around Jamestown. In the former 

 district there are frequent alternations of lava, ash, and sandstone, 

 the even bedding and passage of sandstone into ash, either laterally 

 or vertically, pointing conclusively to sub-aqueous eruptions. The 

 later flows were pi'obably subaerial. 



At the close of the volcanic outbursts, after 2000-5000 feet of 

 lavas had been erupted, the area was affected by gentle folds by 

 which the direction of flow of the Kraai and Orange Rivers was 



