Boulder from Moltnio Sandstone. 'Ml 



Note on a quartzite boulder from the Molteno sandstone. 



By E. H. L. SCHWARZ. 



In going over the geological collection in the Albany Museum, 

 which has been recently entrusted to my charge, I have found 

 portion of a quartzite boulder from the Molteno sandstone. No. 

 45, from Modder Poort in the Stormbei^g, presented by Mr. E. J. 

 Dunn. The substance of the ])oulder is quartzite, and it is of a 

 kind that is of common occurrence in certain zones of the Molteno 

 beds, especially near the coal seams. Green (1) notes boulders of 

 this nature exceeding the size of a man's head : Molyneux (2) men- 



•fr*/ 



Portion of a boulder from the Molteno sandstone, Modder Poort, showing 



pyrites ci-ystals just below the original surface. About half natural size. 



Albany Museum, Eock collection, No. 45. 



tions them occurring not onlj^ in the sandstones above the coal, 

 but in one case, at Indwe, in the parting between two seams of 

 coal. The latter author says the boulders ai^e of exactly the same 

 composition and condition as the quartzites (Table Mountuin 

 series) of the Zwai'tebergen. Dunn (15) says that the conglomerate 

 invariably covers the coal seams, although coal is not necessarily 

 found beneath, that is to say, the conglomei-ate beds are more 

 persistent than the coal seams; the boulders are principally of 



(1) Report on the coals of the Cape Tolony, 1(S8)5, p. 7. 



(2)Report on the geology of the Karroo and Stoi-mberg, LSiSl, p. 'il. 



(;5) lieport on the Stormbei-g Coal Field, 1878, {). 17. 



