60 PEOCEEDINGS OP THE GEOLOGICAL SOCIETY. [DeC. 7> 



shales, sandstones, and calcareous grit contains the same forms of 

 plants, as well as reptilian remains of Dicynodon, and lies conform- 

 ably on a boulder-bed, which gives the impression that it was formed 

 on the spot, and was not transported by the action of water. It 

 is also remarkable, and an observed fact, that this boulder-bed of 

 Southern India passes gradually into the succeeding shales and 

 sandstones, which have been termed by the Indian geologists "the 

 Ootatoor plant-beds." A lithologically similar boulder-formation I 

 have also seen at the same horizon in the Cape Colony, passing 

 beneath the blue Karoo shales ; and I am pretty certain that Mr. 

 Bain and many of our African geologists have taken this boulder- 

 bed, at many localities, for an igneous trappean rock. Mr. Bain (see 

 his map) calls this boulder-bed, which dips under the " Ecca-beds " 

 of the " Pataties Eevier," " Claystone Porphyry." There is certainly 

 a basaltic melaphyre, forming beds of considerable extent in this 

 lowest part of the Karoo formation, as, for instance, can be seen 

 near Platte-fontein, in the great Karoo; but this trap does not 

 belong to the extensive beds of boulders at the base of the " Pata- 

 ties Eevier " shale. At first sight the trap and the boulder-bed 

 have piany similarities, as the material of the boulders is partly de- 

 rived, from igneous rocks. Dr. Sutherland thinks that the boulder- 

 bed was formed by glacial action, and tries to prove it by the ob- 

 served fact of grooves and furrows on the plateaux of the Table- 

 Mountain Sandstone. These grooves, quite similar to those in our 

 Alps, occur in great abundance on the sandstone of the Ifumi river, 

 about twenty miles south of Durban. 



The greenstone (melaphyre ?) has found its way through this for- 

 mation at many places, and forms beds between the strata of it. 

 The greenstone contains a great quantity of pebbles of older rocks 

 imbedded, which give it a speckled appearance. But it seems that 

 the greenstone eruption happened at the earliest period of the form- 

 ing of the Karoo beds, as the " kopjes " of greenstone are only found 

 in the lowest strata of the " Pietermaritzburg shales," and in the suc- 

 ceeding sandstones. The series of greenstone " kopjes," which runs 

 from the Ingeli Range in Kaffirland up through Richmond, York, 

 and Greytown to the Tugela river, is of practical importance, as in 

 it, or in the direction of its strike, the occurrence of copper ores can be 

 traced through the whole of South Africa. Besides this Trappean 

 greenstone, a second igneous formation may be found within the 

 Karoo series, the so-called amygdaloid rock, which caps many of the 

 heights of the upper Karoo beds, and often forms extensive beds be- 

 tween them. From it are derived the various kinds of chalcedony, 

 agates, rock-crystals, and topazes which are so plentiful in the 

 rivers of the Pree States and Natal. 



5, The Cretaceous RocJcs of Souili Africa. — Between the rivers 

 Umtamfuna and Umzambane, about five miles from the southern 

 boundary-line of Natal, on the south-eastern coast of Africa, some 

 deposits are found which at first sight seem to be of the same ma- 



