248 PROF. A. n. &REEN Om THE GEOLOGY AXD 



Corresponding to these lithological distinctions, there are differ- 

 ences equally well marked in the physical features of the tracts 

 occupied by the three groups. 



The Ecca Beds have been bent into a number of folds, whose axes 

 range approximately east and west, and they consist of alternations 

 of hard and soft beds. The usual result in such a case is to produce 

 a country traversed by long parallel ridges running along the 

 outcrops of the hard beds, and intervening valleys following the 

 outcrop of the softer beds. Such is the character of much of the 

 country formed of the Ecca Beds. But other parts of this country 

 are very flat and featureless. The well-known Karoo deserts are 

 on the Ecca Beds, and they are the most monotonous stony plains 

 that can be imagined. I had suspicions, in some cases where the 

 Ecca country was so destitute of feature, that the flatness might be 

 due to there being a thin sheet of Kimberley Shales remaining, and 

 that this levelled over the inequalities in the surface of the Ecca 

 Beds ; but I was never able to verify this conjecture, because these 

 flats are usually deeply buried in superficial sand and debris of 

 sundry kinds. 



The Kimberley Shales form immense rolling plains, generally 

 grassy, and the only marked inequalities are made by outcrops of 

 Trap sheets or dykes. 



The beds of the Karoo and Molteno subdivisions are nearly flat. 

 In such a case alternations of hard and soft beds give rise to terraced 

 hill-sides ; and such is the character of the hills made of these rocks. 

 But there is always a difference, which instantly catches the eye, 

 between a hill-slope formed of Karoo Beds and one formed of ITolteno 

 Beds. In the Karoo Beds the sandstones are thin compared with 

 the intervening belts of shale, and consequently the steep steps 

 formed by the outcrop of the sandstones are narrow compared with 

 the gently sloping terraces that run along the outcrops of the shales ; 

 and the result is that the hill-side, when viewed from a distance, 

 has a striped appearance, and looks as if it were ruled across by a 

 number of thin parallel horizontal bands. In the Molteno Beds, on 

 the other hand, where the shales form a comparatively subordinate 

 item, the great massive grits make lofty, precipitous, and rugged 

 " kranzes," and the shale-terraces are so narrow and so cumbered 

 with grit-debris, that they are scarcely recognizable a little way off. 

 In both the Karoo and Molteno Beds the boldest edges and hill-caps 

 are formed by the escarpments of the great intrusive sheets of 

 trap. 



Coals of the Molterio Beds. — The only workable coals yet discovered 

 in the Colony are found in the Molteno Beds. Detailed sections 

 will be found in the Official Eeports mentioned in the note *, and 



* Colonial Mining Engineer's Eeport on the Coal-field of the Stormbergen. 

 By F. W. North. Presented to both Houses of Parliament by command of 

 His Excellency the Governor. Cape Town, 1878. — Eeport on the Stormberg 

 Coal-fields. By E. J. Dunn. Presented to both Houses of Parliament by 

 command of His Excellency the Governor. Cape Town, 1878. — Eeport on the 

 Coals of the Cape Colony. By A. H. Green. Presented to both Houses of 

 Parliament by command of His Excellency the GoTernor, 1883. 



