ANNIVERSARY ADDRESS OF THE PRESIDENT. Hx 



the existence of the sea animal Ufe of the period, and we may fairly 

 infer no lack of terrestrial vegetation, flourishing beneath the atmo- 

 sphere at the same time. What that vegetation may have been we 

 have yet to learn ; but as the range of the Silurian deposits becomes 

 more known over the earth's surface, in regions where they have 

 either never been covered by more modern deposits, or having been 

 so covered, are now bared by denudation, — and every day we learn 

 more and more of their distribution, — we may expect to obtain a 

 better insight into the kind of plants existing at that remote geo- 

 logical period. 



During his late absence on the continent, our indefatigable col- 

 league. Sir Roderick Murchison, for many years one of the largest 

 contributors of memoirs to our Society on many important geological 

 subjects and districts, did not forget us, and we find him bringing 

 before us, under the head of " Notes on the Geological Structure of 

 the Alps, Apennines, and Carpathians, more especially to indicate a 

 transition from Secondary to Tertiary types, and the existence of Eocene 

 deposits in Southern Europe," the result of his own researches and 

 those of preceding labourers in the same regions ; thus endeavouring 

 to gather up the whole into one systematic view. This is a labour 

 which cannot fail to be properly appreciated by those who have 

 themselves studied the geological structure of the iVlps, Apennines 

 and Carpathians, and are acquainted with the works and memoirs 

 written upon these mountains, from the researches of the justly ce- 

 lebrated De Saussure to the present time, and among which are in- 

 cluded the wi'itings of Sir Roderick Murchison and Professor Sedg- 

 wick, published in our Transactions, and an account by Sir Roderick, 

 in 1829, of the sections observed at Asolo and Bassano. 



Amid masses contorted and broken at different periods, accumula- 

 tions of sedimentary matter, effected under various conditions during 

 a long lapse of geological time, changes in the character of many de- 

 posits after they were formed, and huge portions of dislocated rocks 

 thrust up into the atmosphere, so high in some situations as to be 

 covered by perpetual snow and glaciers, and in others most difficult 

 of access, the determination of the state of the general area as re- 

 gards land and water, conditions for detrital accumulations, and the 

 distribution of animal and vegetable life at given and successive geo- 

 logical times, becomes no easy task. We have merely to crumple up 

 the present geological surface of Great Britain into a great north and 

 south range of mountains, accompanied by huge fractures, parts of 

 the general mass, sometimes altered in mineral characters, and here 

 and there forced up so high above the level of the sea as to become 

 covered by perpetual snow and ice, to feel how much the difficulty 

 would be increased of determining the varied relation of its parts 

 from that which we now experience. When we complicate this state 

 of things still more by previous movements, overlaps, differences in 

 the range of original deposits, alterations subsequently effected in 

 them, and by modifications in the physical conditions under which 

 animal and vegetable life has been placed, we can the better under- 

 stand many of those difficulties which have attended the examina- 



