ANNIVERSARY ADDRESS OF THE PRESIDENT. xH 



the atmospliere, or were laid bare by denudation, after the nummu- 

 litic limestone was formed, and consequently after the beginning of 

 the eocene period. For my own part, I have little doubt that these 

 granites are all tertiary, and that they may even have passed from a 

 fluid or semi-fluid state to their present form at an epoch more mo- 

 dern than the eocene period. But although it is only in a few nar- 

 row strips of country, like the Central Alps, that nature discloses to 

 us some of the nether-formed rocks of sach modern geological seras, 

 we cannot doubt that still greater modifications of the interior have 

 extended downwards for many miles or leagues in depth beneath the 

 Alps, and beneath every region, whether of land or sea, which has 

 risen, sunk, or oscillated in level since the fossil shells and zoophytes 

 of the lower eocene period were living in the sea. The imagination 

 of the geologist strives in vain to form a just conception of the extent 

 of these internal modifications of the crust, of which we are only be- 

 ginning to interpret the outward signs. How much fracture and 

 dislocation of solid rock must have taken place ! how much heating 

 and cooling, expansion and contraction, drying and baking, softening 

 and re-solidifying of sedimentary strata! Over how vast an area, 

 and to how great a depth, often hundreds of yards or several miles 

 beneath the surface, have mineral masses been injected by lava, or 

 dissolved by thermal waters, or corroded by acids, or permeated by 

 steam, or impregnated with magnesia, sulphuric acid, or other sub- 

 stances introduced in a gaseous form ! What obliteration has there 

 not been of organic remains, and of the signs of stratification, in the 

 course of the tertiary ages which have elapsed since the nummuhtic 

 strata and incumbent fucoid grits lay submerged beneath the ocean ! 

 Sir Roderick Murchison has given a graphic description of the 

 foldings, so sharp and so often repeated, of a grand succession of se- 

 dimentary strata in the Alps. Among other examples, he has cited 

 one case of extraordinary inversion of large masses in the canton of 

 Glarus, examined by himself and M. Escher, where a limestone of 

 the Jurassic period containing ammonites is, on the one hand, " over- 

 laid by a zone of talc and mica schist, having in parts quite the 

 aspect of a primary rock ;" while in another direction it is continu- 

 ously superimposed for miles on beds of highly inclined flysch of 



* Quart. Journ. of Geol. Soc. vol. v. p. 246. 



