﻿Mr. C. L. Griesbach on the Geology of Natal. 481 



adduces roches moutonnees, moraines, basins, and striae, both north 

 and south of the Stormberg, in British Kafiraria, and even in Lower 

 Albany. He concluded with remarks on the probable succession of 

 periods, and on the former existence of a great southern continent. 



3. « On the Geology of Natal, in South Africa." By C. L. Gries- 

 bach, Esq., Corr. Memb. of the K. K. geologischen Beichsanstalt, 

 and of the K. K. geographischen Gesellschaft, Vienna. 



The author commenced by describing the physical geography of 

 Natal, and then indicated the characters and distribution of the 

 rocks which occur in that country. He stated that the granitic and 

 gneissic rocks do not form the most prominent elevations, but they 

 appear chiefly in the lower parts of river-valleys, and sometimes in 

 small hills. Mica-schists and slates are found associated with the 

 granites. The great plateaux consist of an undisturbed sandstone, 

 which the author identifies with the Table-mountain Sandstone, and 

 which lies horizontally upon the granites and old slates. The tops 

 of many of the table-mountains in Natal are crowned by beds of 

 dark basaltic greenstone. The Karoo formation, which lies in part 

 upon the Table-mountain Sandstone, consists of a vast series of 

 sandstones and shales, some of the latter containing beds of coal. 

 The author agreed with Mr. Tate in regarding these beds as of 

 Triassic age. At the base of the Karoo formation the author de- 

 scribed a boulder-bed, which he was inclined to identify with the 

 rock described by Mr. Bain as ;< Claystone porphyry ; " and through 

 this greenstone has forced its way. On and near the coast of the 

 southern part of Natal, some sandy marls and sandstones belonging 

 to the Cretaceous series were said to occur ; the author gave lists of 

 fossils obtained from these deposits, which he identified with the 

 Trichinopoly series of India. Several of the fossils were described as 

 new species. The author considered that the evidence adduced 

 indicated that, after the development of the Table-mountain Sand- 

 stone, Africa and India formed parts of one continuous continent, 

 afterwards covered by the Cretaceous sea. The area now covered 

 by the Indian Ocean was the basin of a large series of lakes ; and 

 this condition persisted through a long period of tranquillity, lasting 

 through the Triassic to the Upper Jurassic age. The greater part 

 of this continent was then depressed and covered by the shallow 

 Cretaceous sea. The economic mineral products of Natal were men- 

 tioned by the author, who referred to the occurrence of graphite, 

 coal, gold, and copper. 



4. " On the Diamond-districts of the Cape of Good Hope." By 

 G. Gilfillan, Esq. 



Mr. Gilfillan described his going through Colesberg to Hopetown, 

 and thence across the Orange Biver to Backhouse ; and then, after 

 crossing the Yaal, up its right bank as far as Lekatlong. He 

 noticed such diamonds as he saw or heard of, and described the 

 locality as being thickly coated with sand, diamond-bearing gravel, 

 and tufa, hard blue shales occurring here and there in protruding 

 hills. 



