Vol. 50.] DOLOMITE IN SOUTH AFRICA. 565 



quently dissolved or partially disintegrated. In a microscopic 

 section of the Nondweni quartzite the gold appeared to lie chiefly 

 in the calcareous portions of the rock, although some of it was 

 distributed through the quartzite itself. 



Mr. Nicol Brown remarked that the dolomitic limestone at 

 Pilgrims' Rest, which is apparently the ' elephant-rock ' of Mr. 

 Draper, underlies all the country in the neighbourhood. The lime- 

 stone is eroded into valleys at Pilgrims' Creek and along the course 

 of the river Blyde and elsewhere. On the top of the limestone 

 lies a bed of manganiferous earth ; over this come the beds of 

 quartzite and chalcedolite represented by the specimens on the table, 

 and on the top of the whole there are frequently masses of diorite, 

 often decomposed. 



Although the general dip of the strata is fairly represented by 

 about 1 in 13 to the south-west, the local folds and contortions are 

 numerous, and when he commenced to study the district it was 

 almost impossible to follow the stratification. Numerous carefully 

 registered specimens were sent home, and from these the succession 

 of the rocks has been ascertained with some degree of certainty, 

 with this practical result, that the rich gold-bearing zone is found 

 to be immediately above the manganiferous earth. 



Numerous sections of working-faces have since established the 

 succession. It may be noted, however, that there are distinct indica- 

 tions of the gold-bearing beds sometimes running into the limestone, 

 while sometimes the manganiferous earth overlies the gold-bearing 

 beds. On the escarpments very little chalcedolite and quartzite are 

 found detached from the hillside, but on the counter-escarpments 

 very large masses of these rocks are spread over the hillside, and it 

 is amongst these fragments on Brown's Hill that the nuggets 

 exhibited at the Meeting were found. 



The thickness of the limestone is not known ; it has been eroded 

 500 or 600 feet in Pilgrims' Creek, but no bottom has been seen. 

 The rock immediately underlying it is unknown. 



Prof. T. Rupert Jones referred to Mr. Draper's view of the Ecca 

 Beds thinning out, and the Molteno Beds thickening, northwards, 

 in Natal and Zululand, and alluded to a specimen of the dolomite 

 (exhibited by the previous speaker) from the Lydenburg district, with 

 its associated auriferous quartz : this limestone had been tested 

 and microscopically examined at the Royal College of Science, South 

 Kensington. 



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