496 THE DEPTHS OF THE SEA. [cwap.:x 
of this I will quote two passages in two consecutive 
anniversary addresses by Presidents of the Geological 
Society, and we may have every confidence that the 
statements of men of so great weight, made under 
such circumstances, indicate the tendency of sound 
and judicious thought. Professor Huxley, in the 
anniversary address for the year 1870, says :—‘* Many 
years ago' I ventured to speak of the Atlantic mud 
as ‘modern chalk,’ and I know of no fact inconsistent 
with the view which Professor Wyville Thomson has 
advocated, that the modern chalk is not only the 
lineal descendant, so to speak, of the ancient chalk, 
but that it remains, so to speak, in possession of the 
ancestral estate; and that from the cretaceous period 
(if not much earlier) to the present day, the deep sea 
has covered a large part of what is now the area of 
the Atlantic. But if Globigerina and Terebratula 
caput-serpentis and Beryx, not to mention other 
forms of animals and of plants, thus bridge over the 
interval between the present and the mesozoic 
periods, is it possible that the majority of other 
living things underwent a sea-change into something 
new and strange all at once ?” 
And Mr. Prestwich, in the presidential address for 
1871, says :—‘ Therefore, although I think it highly 
probable that some considerable portion of the deep 
sea-bed of the mid-Atlantic has continued submerged 
since the period of our chalk, and although the more 
adaptable forms of life may have been transmitted in 
unbroken succession through this channel, the im- 
migrations of other and more recent faunas may 
have so modified the old population, that the original 
1 Saturday Review, 1858: ‘Chalk, Ancient and Modern.” 
