468 Reviews — Jenkins^ Hypothetical Continents. 



theory of Professor linger. He believes that the Swiss Miocene 

 plants were derived from America during the Eocene period, by way 

 of an Atlantis which existed during the early Tertiary epoch, and 

 that they migrated at the close of the Miocene period towards 

 America by way of Northern Asia and Japan, that is to say, along 

 the route suggested by Professor Asa Gray. This theory is borne 

 out palceontologically by the fact that the flora of America seems to 

 have undergone little or no change in facies since the Cretaceous 

 period, and geologically by the evidence brought forward by Mr. 

 Searles Wood, Jim., in support of his view of a great Post-cretaceous 

 east and west Atlantic continent (see Phil. Mag., 4th Ser., Vol. xxiii. 

 p. 277). 



Another hypothetical continent is the one proposed by Dr. Sclater 

 to account for the affinity of some of the mammals of Madagascar to 

 some living in Hindostan, and of other animals to certain West 

 Indian forms, as well as the diiferende of the Madagascarian fauna 

 from the African. This continent was supposed to stretch from 

 Hindostan through Madagascar to the West Indies, and to include 

 only a small portion of what now constitutes the continent of Africa; 

 and it received from its proposer the name of Lemuria. 



In opposition to this view, Mr. Jenkins states that there is no 

 physical evidence in support of it, and that it is quite possible to 

 explain all the facts by the aid of paleontology without having 

 ' recourse to it, although our ignorance of the palgeontology of Mada- 

 gascar renders somewhat difficult what more perfect knowledge Avill 

 doubtless very much simplify. The chief facts adduced are the 

 aflinity of the European Eocene Mammals to existing South 

 American forms, the absence of New World monkeys from the 

 Tertiary deposits of the Eastern Continent, and the commencement 

 of the prevalence of Old World types at a later period than the 

 Eocene. Mr. Jenkins therefore infers that the West Indian species 

 represented in Madagascar may have travelled by way of the Eocene 

 Atlantis to Europe, and have migrated thence to Madagascar at a 

 later period. The absence of New World monkeys from the Miocene 

 deposits of Europe supplies him with an additional argument in 

 favour of the Atlantis having existed in early Tertiary times. Had 

 it been of Miocene age, it seems improbable that New World 

 monkeys should not have migrated to Europe in company with the 

 American plants ; but as we have no trace of them in Eocene 

 deposits, their absence from Europe may be explained by Ihe fact 

 of their non-existence at that period. 



One element of uncertainty in these inquiries is " the probability 

 of a great Pacific continent haAdng formerly imited the Old and 

 New Worlds on that side, for we know that that great region is 

 even now an area of depression ;" but Mr. Jenkins thinks that this 

 consideration " would more nearly affect the relation which formerly 

 existed between Australia and South America than the regions which 

 now concern us." 



The foUo^ving are the conclusions at which Mr. Jenkins has 

 arrived : — 



