pbesIdent's address. lOi 



nodules of all sizes, from minute grains to the dimensions of 

 a cricket ball. The composition of these nodules has been found 

 by Mr. Buchanan to vary greatly, "different nodules containing 

 different quantities of mechanically admixed mud, and the num- 

 ber of different elements found in them is very large. Copper, 

 iron, cobalt, nickel, manganese, alumina, lime, magnesia, silica, 

 and phosphoric acid have been detected in large numbers. "'^" The 

 skeletons, both shark and cetaceans, are dissolved, but the teeth 

 of the former and the ear-bones of the latter resisting the action 

 of the waters appear to be scattered over the surface of the Eed 

 Clay in vast numbers. At the ' Challenger's^ Stat. 307 the trawl 

 brought up over one hundred sharks' teeth and thirty ear-bones 

 of whales. As a consequence of the destruction of all calcareous 

 depositions, and of the very slow rate at which we can conceive 

 a bed to be laid down, which is dependent upon the decomposi- 

 tion of volcanic debris transported from volcanoes at a great dis- 

 tance, it may be assumed that the rate at which the Eed Clay 

 is formed must be incalculably slow. The Eed Clay and its 

 varieties appears to extend in gently undulating plains over the 

 deepest depressions of the crust of the earth, and to cover no 

 less than one hundred millions of square miles, at a depth seldom 

 less than 2,500 fathoms, or nearly three miles beneath the sur- 

 face of the sea. The Fauna which inhabits this vast region 

 represents therefore the occupants of one haK of the entire sur- 

 face of the earth. It is, remarks Sir Wyville Thomson, ' ' a Fauna, 

 not certainly of extreme poverty, and very special in its nature ; 

 its speciality consisting mainly in its great uniformity and in 

 the prevalence of certain types. There is every reason to believe 

 that the existing physical condition of this area date from a very 

 remote period, and that the present Fauna of the deep sea may 

 be regarded as being directly descended fi'om Faunae which have 

 successively occupied the same deep sea. In the meantime, 

 changes involving lesser depths have been accompanied by the 

 appearance and disappearance of the land and shallow water 

 faunae of the Jurassic, the Cretaceous, and the Tertiary periods. 

 That the present abyssal fauna is the result of progressive change 



* Proc. Eoyal Soc. Edinb., IS., 1878. p. 288. 



