1855.] SUTHERLAND — NATAL. 467 



tortuous course, and is flanked on both sides by the table-hills, which, 

 curious as it may appear, are at a higher elevation above the sea. 

 The Table-hills are composed of a rudely stratified sandstone, vpith- 

 out fossils, and containing rounded pebbles of gneiss, quartz, clay- 

 slate, and other metamorphic rocks. The granite is very rough- 

 grained, almost porphyritic, and in some instances large masses are 

 seen protruding through, and resting in, beds of the same material, 

 vv^hich has undergone some peculiar decomposing process. As v*^e 

 advance inland, the beds of sandstone and shale are of much greater 

 thickness than on the coast. In one or two instances beds of basalt 

 have been cut through to a depth of nearly 300 feet by the river. 

 Such deep beds give rise to a somewhat terrace-like character in the 

 contour of the country, from the protrusion of the granite to the 

 Draakensberg Range. 



The sea-coast is in some places fringed with reefs of the dark 

 basaltic rocks. In other parts large dunes of sand, containing sea- 

 shells in a fragmentary state, are thrown up by the wind, and, from 

 the large proportion of lime they contain (70 per cent, of the car- 

 bonate), they soon become consolidated into stone fit for building- 

 purposes *. These dunes are, for the most part, covered with a rank 

 verdure or a low thick and impenetrable bush, in which land-shells 

 are abundant, the impressions of which are not unfrequently met 

 with in the newly constructed sandstone. The rivers, with a descent 

 of about 40 feet in the mile, flow very rapidly, and bring down great 

 quantities of detrital matter in a highly subdivided state. This 

 becomes deposited at their mouths to form rock, which not unfre- 

 quently is found to include the enduring shells of Oysters and other 

 littoral molluscs f . The water sometimes bears down fine debris of 

 dark greenstone, which, alternating with the lighter- coloured de- 

 tritus, forms a deposit in which several strata can be counted in the 

 space of a single inch. 



The recent deposits in the upper parts of the district yield fine 

 agates, derived from dykes of amygdaloidal rock. 



The Quathlamba Range appears to be composed of alternating 

 strata of greenstone and the shaly rocks of the Colony. It attains a 

 height httle less than 9000 feet. ' 



The copper of the Natal District, and of the district of the Free 

 Republic beyond the Vaal River (one of the chief branches of the 

 Orange River), occurs in the form of malachite in highly contorted 

 gneiss, the mica of which is not unfrequently replaced by hornblende, 

 thus forming a laminated syenitic rock. From the diffusion of the 

 ore in the rock, and the readiness with which the outcrops are 



* [See also Capt. Nelson's Observations on these rocks of ^olian formation on 

 the South African Coast and elsewhere, Quart. Journ. Geol. Soc. vol. ix. p. 206.] 



t The author incidentally alludes to the richness of the existing raolluscan 

 fauna, both of land and sea, on the Natal Coast, and the characteristic difference 

 existing between it and that on the coast of the Cape Colony, — a difference arising 

 from the heating influence of a current flowing southward along the shore from 

 the Equator, through the Mozambique Channel. 



