472 THE DEPTH'S OF THE SEA. [chap. x. 



unrecorded time ; and that it would be inadmissible 

 to speak of two portions of the same continuous 

 deposit, however distant the times of their deposition 

 might be, and however distinct their imbedded 

 faunae, as belonging to different 'Geological periods.' 



It was certainly in this sense that in an address to 

 a popular audience in April 1869 I ventured to state 

 my belief that it is not only chalk which is being- 

 formed in the Atlantic, "but the chalk, the chalk of 

 the cretaceous period." Sir Charles Lyell says, in 

 summing up his objections to this view, 1 " The 

 reader will at once perceive that the present Atlantic, 

 Pacific, and Indian oceans, are geographical terms 

 which must be wholly without meaning when applied 

 to the eocene, and still more to the cretaceous period, 

 so that to talk of the chalk having been uninter- 

 ruptedly formed in the Atlantic is as inadmissible in 

 a geographical as in a geological sense." I confess 

 I do not see the geographical difficulty ; the 

 "Atlantic ocean" is, undoubtedly, a geographical 

 term, but the depression under discussion occupies 

 the area at present expressed by that term, and to 

 use it seems to be the simplest way of indicating its 

 position. We believe that the balance of probability 

 is greatly in favour of the chalk having been unin- 

 terruptedly forming over some j>arts of the area in 

 question, and our belief is founded upon many con- 

 siderations, physical and palseontological. 



All the principal axes of elevation in the north of 

 Europe and in North America have a date long an- 

 terior to the deposition of the tertiary, or even of the 



1 The Student's Elements of Geology. By Sir Charles Lyell, Bart., 

 F.K.S. London, L871. P. 265. 



