58 SECTIONAL ADDRESSES 



manner, reminded us of Huxley's exposition of how first Hutton and then 

 Lyell rescued our science from the stultifying catastrophism of the 

 Noachian flood tradition by founding the Uniformitarian school, whose 

 touchstone was the principle just mentioned, the interpretation of the past 

 by reference to causes now in operation. Huxley further demonstrated 

 how this swing of the pendulum was damped, and (as Prof. SoUas later 

 pointed out) the most striking advance in geological thought engendered, 

 through the publication of The Origin of Species, by which Evolutional 

 Uniformitarianism became our watchword. The new conception of the 

 evolution of life on the earth was accompanied, as every great forward move- 

 ment must be, by theories and hypotheses thrown out far in advance of the 

 army of accumulated facts. Some of these outposts had to be abandoned ; 

 others were able to dig themselves in. A long period of consolidation 

 in the battle for enlightenment was inevitable. The onus of testing and 

 proving the general truth of evolution and of describing the nature of 

 evolutionary changes has naturally fallen on the geologist. Such a task, 

 involving laborious stratigraphical and palaeontological studies, was one 

 after his own heart, for he was enabled while pursuing it to follow other 

 geological interests. But it was not a task that could be hurried, since 

 it included the full investigation of stratigraphical successions at home 

 and abroad. Indeed, the present detailed studies of the rocks and fossils 

 of small divisions of the geological record had inevitably to become a 

 leading feature in our publications ; and, while they bear witness to the 

 fact that the necessary labour is far from finished, they unfortunately tend 

 to repel the student of other sciences. Further, during the last fifty years 

 there has come to us the realisation that not only life, but environment 

 and crustal movement have been undergoing steady changes in character 

 throughout geological history ; and we cannot disregard the obvious 

 connection between them. To Eduard Suess we owe the first exposition, 

 in his Das Antlitz der Erde, of tectonic geology on a regional scale, a branch 

 of the science which has grown apace. In this study, geologists abroad 

 (whose lines are cast in more favourable places) have taken a relatively 

 greater part than those in Britain. As a branch of science that collates 

 and co-ordinates a huge mass of facts, not always clearly related, but from 

 which we may look forward to illuminating generalisations, regional and 

 tectonic geology must be recognised as a striking feature of our science 

 to-day. 



while realising, however, that detailed stratigraphical investigation and 

 field-mapping, with its great British tradition behind it, must remain an 

 essential, we should not lose sight of the fact that geology is also an 

 experimental science. Sir John Flett, in his address to the section at 

 Edinburgh in 1921, reminded us that the earliest synthetic work on the 

 chemistry of igneous magmas and rocks was accomplished by James Hall, 

 who actually melted and recrystallised rocks in the laboratory and investi- 

 gated the conditions of temperature and pressure that resulted in the 

 recrystallisation of limestone. During the past century, a long line of 

 experimenters has followed Hall's footsteps, but the elaborate equipment 

 now required for physico-chemical investigations in petrology has been 

 a deterrent to work in our impoverished Universities. The wonderful 



