84 DK. p. H. HATCH — GEOLOGY OP THE [Feb. 1 898, 



degree of uniformity in regard to the sequence and continuity of 

 the different conglomerate-beds. Thus, the Bezuidenville borehole, 

 put down at a point 5800 feet south of the outcrop of the Main 

 Eeef at the Meyer & Charlton Mine, near Johannesburg, intersected 

 the Main Keef at 3200 feet, the dip at that depth being about 27°. 

 A section of the strata passed through is as follows : — 



Feet. 



Quartzite with shale-bands 1120 



Quartzite with conglomerate-beds (Bird Series) 350 



Quartzite with oocasional epidiorite-dykes 1550 . 



Quartzite with couglomerate-beds (including South and 



Main Eeef Series) 230 



Quartzites 330 



Shales to bottom of borehole 160 



A borehole (' New Eand Mines borehole '), put down 3500 feet 

 south of the Aurora West, struck the Main Reef at a depth of 

 2040 feet, the dip being 27°. This borehole being located a few 

 feet north of the outcrop of the Bird Eeef Series, it just missed 

 them. It passed through 2600 feet of quartzites and grits with 

 epidio rite-dykes. At 2030 feet the Main Eeef Leader was inter- 

 sected, at 2038 feet the Main Eeef, at 2089 feet the Bird Eeef, and 

 the borehole passed into the Bottom Shales (Hospital Hill Series) at 

 a depth of 2438 feet (see fig. 3, facing this page). 



The Eand Victoria borehole, put down 4400 feet south of the 

 outcrop of the Main Eeef at the Simmer & Jack, intersected the 

 conglomerates of the Bird Series at 400 feet, those of the Livingstone 

 Eeef at 1620 feet, the South Eeef at 2348 feet, and the Main Eeef 

 at 2390 feet. 



The Chimes Mines borehole, put down 3820 feet south of the 

 outcrop of the Main Eeef at the Kleinfontein Mine, 7 miles east 

 of Boksburg, passed through the upper portion of the Bird con- 

 glomerates at 210 to 228 feet, and through the lower portion of the 

 same series at 430 to 454 feet. It intersected the Chimes or South 

 Eeef Series between 1154 and 1194 feet, the Main Eeef Leader 

 at 1738 feet, and the Main Eeef at 1754 feet. The dip at this 

 depth was 22°. 



The following section, which gives the estimated thickness of the 

 different beds of the Witwatersrand Series, has been constructed 

 partly from information obtained by boring, partly from measure- 

 ments across the outcrop of the beds : — 



Feet. 

 From the base of the Klip- 1 conglomerates and ^ 



riversberg Amygdaloid to the j-quai'tzites (Elsburg V 3000 



base of the Elsburg Series ... J Series) J 



Kimberley Series to Elsburg Series, quartzites 4000 



Kimberley Series, conglomerates 440 



Kimberley Series to Bird Series, quartzites 1450 



Bird Series, conglomerates 100 



Bird Series to South Eeef, quartzites 1700 



South Reef to Main Reef, quartzites 140 



Main Reef Seiies, conglomerates 20 



Main Reef to Bottom Shales, quartzites 400 



Total.... 11250 



