246 PKOF. A H. GKEEJsT OlvT THE GEOLOGY A^N^D 



occur), frequently red with greenish bands and blotches (recalling 

 forcibly our English jS'ew Eed Claris), or dark greyish-purple 

 or buff. It is useful -for purposes of identification to note that the 

 shale-bands in the Xaroo Beds are, as a rule, much thicker than the 

 sandstones, Eain mentions (loc. cit. p. 55) that the Karoo Beds 

 contain nodules of greyish-blue argillo-ferruginous limestone, 

 which often contain reptilian remains. I saw such near Burgersdorp 

 in a bed in which Dr. Kamemeyer had found many reptilian bones. 



There is a gradual passage from the Kimberley Shales into the 

 Karoo Beds. The shales become more sandy and harder, beds of 

 sandstone put in and become gradually more numerous, and so we 

 pass from a group which is practically all shale to one in which 

 sandstone is an important item. Cohen states that the matrix of 

 the Karoo sandstones and shales contains carbonate of lime (Joe. cit. 

 p. 218). When we remember that great deposits of calcareous 

 tufa cover a large portion of the Karoo country, it seems not 

 unlikely that this ingredient is not original, but has been introduced 

 by infiltration. 



The fossils of the Karoo Beds which have attracted most attention 

 are the reptilian remains discovered by Bain. These have been 

 described by Professors Owen and Huxley. 



Bain mentions shells from this formation at Mankaza Port, twenty 

 miles north-east of Fort Beaufort (loc. cit. p. 55), and also some 

 shells from Graaf Eeinet (loc. cit. p. 225), which have been doubt- 

 fully referred to freshwater genera. Estheria is quoted by Prof. 

 Bupert Jones *. 



Ferns (Glossopteris, Rubidgea, ? Dictyopteris), with PhylJotheca 

 and other plant-remains, are recorded by various authors f ; but, so 

 far as I know, these have not been fully described and tabulated. 



The evidence is imperfect and partly negative ; but, so far as it 

 goes, it points to the conclusion that the Karoo Beds are a fresh- 

 water deposit. 



(9 a.) The Molteno Beds are, like the Karoo Beds, made up of 

 alternations of sandstones and shales, but there are several very 

 marked points of difference between the two groups. The sand- 

 stones of the Molteno group are some of them finely grained and 

 undistinguishable from those of the Karoo Beds ; but many of them 

 are very coarse grits, made up to a considerable extent of large 

 grains of glittering quartz, and with very little felspathic matter. 

 These grits frequently pass into conglomerates containing pebbles 

 of white vein-quartz. Still coarser conglomerates are occasionally 

 met with, in which there are boulders of quartzite larger than a 

 man's head. The shales of the group are for the most part grey or 

 dark-coloured ; red shales are not entirely wanting, but they seem 

 to be very rare. Also, while in the Karoo Beds the shale-bands are, 

 as a rule, thicker than the sandstones, the reverse is the case in the 

 Molteno Beds ; in them the bulk of the subdivision consists of thick 

 beds of massive grit, and the shale-bands which lie between them 



* Geol. Mag. [2] vol. v. p. 100. 



t Quart. Journ. Geol. Soc. toI. xxiii, (1867), p. 140. 



