Vol. 56.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lxV 



metamorphic rocks were thought to form a sort of passage between 

 igneous and aqueous rocks, to be neither fish, flesh, nor fowl, neither 

 one thing nor the other : it was hardly realized that both igneous 

 and aqueous rocks alike had been influenced by mighty changes 

 brought about by heat, by pressure, and by movement ; regional 

 and dynamic metamorphism were terms unknown. Nor were those 

 slow but constant actions that go on nearly everywhere, from the 

 surface downward, at all appreciated ; even yet, perhaps, we have 

 much to learn about them. 



Another marked advance is in our knowledge of great earth-move- 

 ments and of mountain-structure, whether of existing ranges or 

 of those now more or less destroyed. Overthrust-faults, crush- 

 conglomerates, and various other phenomena now accepted as 

 fundamental articles of faith, were not known in my early days, 

 and had views such as those to which we are in the habit of calmly 

 listening been brought forward then their authors would have been 

 deemed arch-heretics or madmen. 



The study of those surface-actions by which the features of our 

 earth have been carved out has greatly progressed : indeed this 

 subject was little considered forty years ago, while now the various 

 methods of erosion and their resultant forms are well understood 

 and repeatedly described. 



As an illustration of our advance in some of these matters I 

 would point to two Geological Survey Memoirs of recent date. In 

 the earlier of these 1 the geological structure of part of Argyll- 

 shire and the metamorphism and deformation of the rocks are 

 dealt with in great detail, part of the memoir being almost a text- 

 book on schistose rocks. The other is the fine Memoir ' On the 

 Silurian Rocks of Britain,' ' 2 the most important publication of the 

 past year on our home-geology, dealing with penological, palseonto- 

 logical, physical, and stratigraphical problems. This work is of much 

 more than local interest, and if any further justification for the 

 joint award of a Murchison Medal to each of its chief authors last 

 year had been needed, this memoir would have fully supplied it. 



Turning, finally, to the stratigraphical branch of our highly divisible 

 science, on which branch alone am I qualified to speak at length, 

 one most notable advance has been in the more detailed character 



1 ' The Geology of Cowal,' pp. viii & 333, with 10 plates, 1897. 



2 Vol. i: Scotland, pp. xviii & 749, with 28 plates & map, 1899. 



