Hypothetical Continents. 97 



gascar is so extremely scanty and indefinite that we cannot 

 quote a single fact derived therefrom in support of either 

 view; but doubtless future discoveries will prove the proba- 

 bility or the impossibility of the hypothesis I have here 

 advocated. I will just venture to anticipate one element of 

 uncertainty in future inquiries into this subject, namely, the 

 probability of a great Pacific continent having formerly united 

 the old and new worlds on that side, for we know that that 

 great region is even now an area of depression. It seems 

 probable, however, that this consideration would more nearly 

 affect the relation which formerly existed between Australia 

 and South America, than the regions which now concern us. 



In the foregoing pages I have endeavoured to establish the 

 following conclusions : — 



1 . That hypothetical continents belong* to two categories ; 

 namely, first, those supported by physical evidence, and, 

 second, those unsupported in that respect. 



2. That while the miocene Atlantis and Lemuria come into 

 the second category, the eocene Atlantis and the possible 

 Pacific continent come into the first. 



3. That the theory of a miocene Atlantis and that of 

 Lemuria each explains only one portion of the palseontological 

 facts that call for elucidation ; while the theory of an eocene 

 Atlantis explains the whole of the facts of both cases. 



4. That for these reasons it is probable that the miocene 

 fauna and flora of Europe came from America during* the 

 eocene period by way of the eocene Atlantis ; and that since 

 the miocene period they spread over Asia and Africa and the 

 eastern seas, and that a part of the flora returned to America 

 by way of Northern and Central Asia and Japan. 



5. That the fact of American cretaceous and eocene plants 

 uniformly occurring in older deposits than a European paleeon- 

 tologist would, a priori, consider possible,* is of itself a most 

 remarkable confirmation of two theories; namely (1), that 

 organisms have migrated from west to east (e. g., from America 

 to Europe in eocene times) ; and (2) that deposits in the old 

 and new worlds should be treated as homotaxeous,f and not 

 as contemporaneous. 



* See Dana's Manual of Geology, p. 510. 



f Quarterly Journal, Geological Society, Vol. xyiii., p. 52 ; and Quarterly 

 Journal of Science, Vol. ii., No. 8, p. 622. 



VOL. X. — NO. II. 



