514 Notices of Memoirs — Mr. G. W. Stow — 



Conclusion. — In this, and a preceding paper already referred to, I 

 have endeavoured to point out, firstly, what are the actual forms of 

 certain volcanos, and secondly, the principal causes which produce 

 and subsequently modify these forms. 



Taken as a whole, these causes are very varied in their character. 

 If we examine them singly, we can but barely form an idea as to the 

 nature of their actions, and when we remember that, not only are 

 they irregular in themselves, but that they act irregularly in their 

 relations to each other, we see that the task of unravelling their 

 complications becomes quite hopeless. In cases like this mathe- 

 matical investigation helps us to obtain a clearer idea of an action, 

 but it is seldom that it can be made to measure it. All that we can 

 do is to fall back upon opinions, observations, and common-sense, 

 the ordinary weapons which build up or destroy geological hypo- 

 theses. 



NOTICES OIE 1 nVCIEIMIOIIR-S- 



I. — Coal and Iron in South Africa. 1 

 (From the " Friend of the Free State," etc., Bloemfontein, August, 7, 1879.) 



THE following extracts from Mr. Gr. W. Stow's Geological Report 

 on the Orange-River Free State show what immense supplies 

 of coal and iron-ore await the arrival of the miner in that region : — 

 Taking the road to Rietvlei, before reaching the homestead of 

 Fieldcornet Stoffel Bosnian, the old partially metamorphosed sand- 

 stones 2 are again met with, cropping up above the surface. Here 

 they are pinkish- white, fine-grained, and dip to the W.S.W. at an 

 angle of 54° to 55°. The most important feature connected with 

 their appearance at this spot is the great beds of iron-ore associated 

 with them. These become distinctly visible immediately in the rear 

 of Mr. Bosnian's house. I was first struck in finding fragments of 

 these ferruginous rocks employed in building portions of the fences 

 round the land and kraals. Once upon their trail they are easily 

 traced for miles. At one spot, about a couple of miles from the 

 homestead, three beds are most clearly exposed. They are as 

 follows : — On the top of a high bank the first bed is exposed on the 

 surface for a breadth of about sixty feet, with a westerly dip of 

 about 60° ; about 450 feet from this a second bed makes its ap- 

 pearance, with a surface exposure of 45 feet, continuing towards a 

 lower bank on the right about 750 feet distant ; a third, but smaller, 

 bed next crops out, with a surface exposure of about 25 feet. The 

 dip of these last is similar to the first. These beds, therefore, run 

 parallel one to another, and are regularly interstratified with the 

 sandstones. The true thickness of the respective beds is : first 

 bed, 50 feet ; second bed, 40 feet ; third bed, 20 feet ; making a 

 total thickness of 110 feet. A considerable quantity of magnetite, 

 or magnetic iron-ore, is found in them, which quickly makes itself 



1 Kindly communicated by Prof. T. Rupert Jones, F.E.S. 



2 See Quart. Journ. Geol. Soc. vol. xxx. p. 624, etc. 



