( Ixxix ) 



Oedinary Monthly Meeting. 

 Jttly 30, 1902. 

 Sir David Gill, President, in the Chair. 



The Minutes of the last meeting having been read and confirmed, 

 the following nominations were made : Messrs. Palmer, Campbell, 

 Young, and Herbert. Dr. A. E. Thompson and Dr. Fismer were 

 elected members of the Society. 



A motion by Dr. E. B. Fuller fell through owing to the absence 

 of the proposer. 



Mr. E. H. L. ScHWARz read a paper on the Volcanoes of Griqua- 

 land East. 



In the district of Matatiele the Geological Survey has recently 

 discovered nineteen or twenty old volcanic necks which are 

 undoubtedly the vents out of which the amygdaloidal lavas that 

 cover the Drakensberg were erupted. The necks are either entirely 

 filled up with solidified lava, or with ashes that were thrown out and 

 fell back into the vent, or with both lava and agglomerate. An 

 actual lava-flow was discovered in connection with a vent on the 

 crest of the mountains, which, by the removal of the overlying lava- 

 flows, shows the original surface formed on cooling. 



The main interest of the discovery is that the volcanoes form a 

 line running north-east, and parallel to the main watershed of South 

 Africa. This is traversed once only by the Orange Eiver. A map 

 of the rivers of South Africa shows that the watershed runs uninter- 

 ruptedly past the region where the volcanoes are present, so that at 

 one time, apparently, the rivers came off it, at one side flowing 

 south-east and on the other north-west. The volcanoes were thrown 

 across this system of rivers, and the waters that originally flowed 

 into the Indian Ocean were turned back and forced across the 

 watershed. 



The volcanoes therefore were active after the Karroo had become 



