46 Correspondence — Dr. R. F. Scharff. 



1918. " The Disintegration of Wolfram," a letter published in the 

 Mining and Scientific Press, San Francisco, September, 1917, by 

 myself ; The Ore Minerals of the Tavoy District, by J. Morrow 

 Campbell, published privately, but available from Messrs. Rowe & Co., 

 Kan goon. 



As far as I understand their published views. Dr. W. R. Jones 

 supports the pneumatolytic theory of the origin of the deposits, 

 while Mr. J. Morrow Campbell believes that highly siliceous water 

 was the agent which leached tin and tungsten from the magma and 

 at quite moderate temperatures deposited cassiterite, wolfram, and 

 associated minerals in veins. 



J. Coggin Brown, 

 Assistant Superintendent, Geological Survey of India. 



Tavoy, Burma. 



October 1, 1918. 



THE FAUNA AND FLOEA OF THE GEE AT ICE AGE. 

 Sir, — The remains of the past fauna and flora have frequently 

 been utilized in supporting the theory of an Ice Age. But little 

 justice has been done to this subject, although it has been maintained 

 by some authorities that the geological history of both animals and 

 plants furnish strong evidence in favour of an Ice Age. In Sir 

 Henry Ho worth's series of instructive articles in the Geological 

 Magazine of August, September, and October last he emphasizes 

 some features in the past and present marine fauna of the Baltic 

 which deserve very careful consideration. His remarks about 

 Yoldia and its distribution apply with equal force to dozens of other 

 species of marine organisms. The argument that because a species 

 now lives at a certain depth in the Arctic Ocean it must have lived 

 at the same depth during the Ice Age much further south is a 

 fallacy, as Sir Henry Howorth points out. Although some forms of 

 animal and plant life readily adapt themselves to changes of 

 temperature in the course of their migrations most of them require 

 for their existence and welfare a uniform temperature. The con- 

 clusions arrived at by Sir Henry Howorth are based on the conditions 

 which obtain almost everywhere near the coasts of Europe at the 

 present day. We may observe Arctic species thriving at considerable 

 depths, while Southern species inhabit the shallow water of the same 

 area. In elucidating the geological history of the Baltic these 

 conclusions, with which I entirely agree, are of the highest 

 importance. 



It. F. Scharff. 

 National Museum, Dublin. 

 November 23, 1918. 



OBITUARY. 



JOHN DUER IRVING- 



Born August 18, 1874. Died July 20, 1918. 



John Doer Irving, the son of Professor R. D. Irving, of the 



University of Wisconsin, was educated at Columbia University, and 



