PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. 3 



November 20, 1889. 



W. T. Blaneord, LL.D., F.E.S., President, in the Chair. 



Nagayuke Asano, Esq., Assoc. R.S.M., care of Marquis Asano, 

 Hongo, Tokio ; Lieut.-Col. T. Couchman, C.E., Melbourne, Victoria ; 

 Frederic H. P. Cresswell, Esq., Assoc. E.S.M., Chile, Yenezuela ; 

 and Thomas Shilston, Esq., 14 Wentworth Place, Newcastle-on- 

 Tyne, were elected Eellows of the Society. 



The List of Donations to the Library was read. 



The Secretary announced that a series of specimens from the 

 line and the neighbourhood of the Main Eeef, East and West of 

 Johannesburg, Witwatersrand Gold Fields, had been presented to 

 the Museum by Dr. H. Exton, F.G-.S., and read the following letter 

 from that gentleman in explanation of them : — 



" Johannesburg, Transvaal, South Africa, 

 7th May, 1889. 



*' Dear Sir, — 



" Having been engaged in making a collection of specimens of 

 auriferous conglomerate from the principal mines in this immediate 

 neighbourhood, I have packed a series of these, which are now in 

 transit and of which you will be duly advised by the transport- 

 agent. They are designed for the Museum of the Geological 

 Society. 



" Commencing eastward of Johannesburg, there are examples from 

 the Black lieef, the Salisbury Mines, Wemmer's, Robinson's, Lang- 

 laagte Estate, and the Paadl Pretoria — this last-named being now 

 under the new appellation of Langlaagte Consolidated. Excepting 

 the Black Reef, these mines are all upon the Main Reef. The 

 Main Reef has a general direction east and west, with a dip 

 towards the south varying from 45° to 80°. In the Salisbury 

 claims the reef is practically perpendicular. 



'• On the south side of the Main Reef, and running parallel to it at 

 a distance of from 15 to 20 feet, is a narrow reef called by the miners 

 the south ' leader/ This varies from 7 to 15 inches wide, and is 

 generally much richer than the Main Reef. 



" At the Wemmer's Co. this south ' leader ' consists of several 

 narrow bands in close contiguity, which are so rich that at present 

 this alone is being worked. I am enabled to send specimens of this 

 * leader,' along with the casing both from the north and south 

 faces. From several other mines there are examples from the 

 casing of the Main Reef as well as of the ' leader.' Among those 

 from the Salisbury there is a piece of a white friable sandstone, 

 which runs in a narrow band parallel to the south ' leader,' and 

 which often runs into the ' leader,' still keeping its distinctive 

 feature, 



