i893. THE BRITISH ASSOCIATION ADDRESSES. 295 



physiologist derives most aid from whatever chemical and physical 

 training he may be fortunate enough to possess." 



UXITORMITARIANISM IN GEOLOGY. 



Mr. Teall's address to the Geological Section is the most 

 remarkable for startling expressions of opinion, and may be regarded 

 as indicating another reaction in the ever vacillating body of 

 enquirers into the history of the earth. Speaking as a petrologist, 

 Mr. Teall remarks that although enormous progress has been made 

 in this science during the last hundred years, there has been com- 

 paratively little advance so far as broad, general theories relating to 

 the origin of rocks are concerned. He even declares his belief, that 

 those who have deserted the old school of Uniformitarians for a 

 certain modern creed of Evolution, will ere long discover their 

 mistake. " The uniformitarian hypothesis, as applied to the rocks 

 we can examine, has assimilated and co-ordinated so many facts 

 in the past, and is assimilating and co-ordinating so many new- 

 discoveries, that we should continue to follow it. rather than 

 plunge into the trackless waste of cosmogonical speculation in 

 pursuit of what may after all prove to be a will-o'-the-wisp." 

 "... The good old British ship, ' Uniformity,' built by Hutton, 

 and refitted by Lyell, has won so many glorious victories in the past, 

 and appears still to be in such excellent fighting trim, that I see no 

 reason why she should haul down her colours either to Catastrophe or 

 Evolution. Instead, therefore, of acceding to the request to ' hurry 

 up,' we make a demand for more time. The early stages of the 

 planet's history may form a legitimate subject for the speculations of 

 mathematical physicists, but there seems good reason to believe that 

 they lie beyond the ken of those geologists who concern themselves 

 only with the record of the rocks." 



Crystalline Schists. 



The earliest sedimentary rocks in Britain, Mr. Teall admits, present 

 some differences from the later rocks in this country, but he doubts 

 whether any conclusions of universal application can be drawn from the 

 fact. The common idea, however, that crystalline schists belong exclu- 

 sively to the earliest periods of the earth's history, and therefore are 

 witnesses of cosmic evolution, is combated in a vigorous manner. " The 

 crystalline schists certainly do not form a natural group. Some are 

 undoubtedly plutonic igneous rocks showing original fluxion ; others 

 are igneous rocks which have been deformed by earth-stresses subse- 

 quent to consolidation ; others, again, are sedimentary rocks meta- 

 morphosed by dynamic and thermal agencies, and more or less 

 injected with ' molten mineral matter ' ; and lastly, some cannot be 

 classified with certainty under any of these heads. So much being 

 granted, it is obvious that we must deal with this petrographical 

 complex by separating from it those rocks about the origin of which 



