254 E. H. X. Schicarz—Rot Springs. 



at the junction of the Table Mountain Sandstone and the Bokkeveld 

 Beds, and that ordinary springs, which are certainly the water 

 returned to the surface after a short course underground, occur 

 plentifully along it; the hot springs, instead of taking advantage 

 of veins or fissures, come up in exactly the same way. In other 

 words, the hot springs at the surface occur in the same manner as 

 the cold ones, though it is probable that the hot water reaches the 

 water-zone through underground fissures. When there is a good 

 exposure of the Malraesbury clay-slates, from which the Table 

 Mountain Sandstone has been removed by denudation, the veins 

 of quartz are seen everywhere traversing the rock ; north of Van 

 Ehynsdorp, indeed, the surface of the ground is so covered with 

 the white quartz which has weathered out of these veins that it 

 looks as if there had been a heavy fall of snow. My first point, 

 therefoi-e, will depend on whether these fissures are being filled by 

 materials from solution in water which is essentially different in 

 origin to that of the surface springs. 



As far as I am aware, no heavy metals, such as gold or mercury, 

 have been found in connection with lavas.^ Dykes are known to 

 contain them in workable quantities, as in some of the acid veins 

 in Australia ; I have even found gold in the dolerite traversing the 

 banket-reefs on the Eand ; also the precious metal occurs in some 

 of the volcanic tuffs of Australia, for instance on the Lyndhurst 

 goldfield, but in all these cases there is a very strong suspicion, 

 or some would say conclusive proof, that the gold has got into 

 the rock by absorption and infiltration, and is not original. At 

 Ono-eluk's Nek, in the Drakensberg, there was a very great gold- 

 rush at one time, and the lavas were prospected to the topmost 

 peaks of the range, but without result.- Should volcanoes be the 

 orifices of pipes that go down to the inmost recesses of the earth, 

 then one would expect oceanic islands and volcanic areas to be the 

 best places to prospect in, instead of the older sedimentary rocks, 

 and the difference to my mind proves that the mineralized beds 

 have been carried beneath the earth's surface to greater depths than 

 those at which volcanoes have their origin. All this seems to point 

 to an essential difference between volcanoes and hot springs. The 

 latter do deposit gold and other heavy metals from solution, as one 

 can actually see now in progress at the Steamboat Springs in 

 Nevada,^ though the process is one that usually goes on at a very 

 o-reat depth. The hot springs may be due to expulsion by super- 

 heated vapoux*, and it seems an obvious explanation when we see 

 the enormous pressure which steam will exert. In the interior of 



[1 Eeference may be made to the occurrence of native iron, which has been 

 discovered in considerable quantities at Ovifak, Disko Island, Greenland, and which 

 was at one time supposed to be of meteoric origin, but has since been shown to be 

 disseminated through an eruptive basaltic rock on the spot, and must therefore have 

 come to the surface from a deep-seated soiu'ce in the interior of the earth. (See 

 K. I. v. Steenstrup in Mineralogical Magazine, July, 1884, vol. vi, p. 1.) — 

 Edit. Geol. Mag.] 



- Ann. Eeport Geol. Commission for 1902, Cape Town, 1903, p. 46. 

 . 3 Becker: U.S. Geol. Surv., Mon. 13, 1888. 



