582 THE GEOLOGY OF THE NOETHERN ETBAI. 



apparently from a vein in the mica-scMst. The mode of occurrence 

 of the emeralds of the Etbai was somewhat similar to that of the 

 emeralds of Siberia and of Salzburg, where the mineral was asso- 

 ciated with mica-schist, while it was entirely different from that of 

 the South American emerald, which occurred in a bituminous lime- 

 stone, supposed to be of Neocomian age. 



Mr. J. W. Gkegoet said that Mr. Floyer was probably using the 

 term ' Nubian Sandstone ' in its old sense, including a series of sand- 

 stones from the Cenomanian to the Carboniferous. He suggested 

 that it was possible that the rock which Mr. Moyer regarded as 

 altered Nubian Sandstone might be much older than the base of that 

 series in Prof. Hull's diagram, which possibly represented another 

 tract of country. 



Dr. Blanfoed also spoke. 



