69 



adjacent portions of the Mediterranean from the Red Sea, the faunas 

 of which are materially distinct from each other. 



Mr. Forbes explored a submarine tract of 300 miles in width, 

 dredging in all depths between 1 and 230 fathoms. At more than 

 100 fathoms, tlie Ijottom often consisted of white chalky sediment, 

 which extended throughout the Egean, and was invariably inhabited 

 by the same species of Foraminifera. At a depth of 200 fathoms 

 Molkisca only, of the genera Tellina, Corbula, Area, and Dentalium 

 were found, but associated with Annelides, Star-fishes, Crustaceans, 

 and Zoophytes. Lastly, he ascertained the range and charac- 

 ters of 500 species of existing Mollusca and of numerous associated 

 lladiata. Among the former were species which live indifferently 

 at all depths between 10 and 150 fathoms, and several of them 

 (including Buccinum semistriatwn, Dentalium quadrangulare, and 

 Pleurotoma crispata) which had hitherto been known only in a fossil 

 state. By this examination he also arrived at the important fact, 

 that such species as are abundant in a fossil are extremely rare 

 in a living state, and tnce versa:, and thus he lays before us the 

 last remnants of a former state of the surface of whose existence we 

 were ignorant, accompanied by the descendants of animals, which, 

 first appearing in small numbers in a pre-existing period, are now 

 attaining their maximum of numerical development. 



Such discoveries. Gentlemen, are most important to the progress 

 of true induction ; and when these researches of Mr. Forbes are pre- 

 sented to you in extenso, as is his intention, each of us will, I doubt 

 not, find in them some illustration of the stony deposits with which 

 we are more familiar. 



I may well, therefore, congratulate the Society on having ob- 

 tained the services of such a naturalist as Mr. Forbes, of whom it 

 has been said by a distinguished foreign contemporary, that " his 

 anatomical knowledge, the accuracy of his thought, and the vigorous 

 precision with which he can estimate the minute differences on which 

 the distinction of species depends, render him a worthy successor of 

 Mr. Lonsdale, and ensure to us that he will render important services 

 to the advancement of Geological Science*". 



Having spoken of those changes in the Society which have taken 

 place through the demise of Members and through official changes, I 

 now proceed to consider the progress of our Science,not merely within 

 the British Isles, but also, as far as I am able, in other parts of the 

 world to which geological researches have been extended. In so 

 doing I shall follow the arrangement of last year, and treat of the 

 rocks of each country in the order of their antiquity, commencing 

 with the most ancient. First dwelling upon the British Isles, I will 

 next advert to Russia, the Caucasus, Asia Minor, Turkey and the 

 Alps, and then in succession to works upon America, the East In- 

 dies and Egypt ; and after an analysis of the recent progress in 

 Palaeontology, I will take leave of you with a brief resume of the 

 principal geological results. 



* Professor Agassiz, Letter to Mr. Murchison. 



