388 Mr. S. V. Wood on the Effects upon Animal Life 



These coincidences have, it is true, been explained by some on 

 the ground that Australia, like the secondary lands, was adapted 

 only for such forms of life, and that the animals most fit to in- 

 habit it have been specially created there ; but this explanation 

 fails completely before our daily experience ; and the explanation 

 of their occurrence must be sought on other grounds. The 

 only explanation which appears to me to be consistent with all 

 the phenomena of the case is, that in these lands we possess 

 remnants more or less isolated of the secondary continents. I 

 by no means pretend that any such coincidences warrant a con- 

 clusion that this isolation has been in each case from the same 

 period. On the contrary, while the Mammalia of Australia 

 (among which occur the only known forms of the true Mono- 

 tremata, the Ornithorhynchus and Echidna) and the birds of New 

 Zealand, coupled with the predominance in the latter country of 

 the fern tribe, conspire to show an isolation of those lands from a 

 remote part of the secondary period, the fauna of the island of 

 Madagascar, comprising as it does (and almost exclusively) the 

 family of the Lemuridse, points to an isolation of that country at a 

 later part of the secondary period*. It will be seen whether or not 

 these conjectures are well founded when future discoveries shall 

 have made us better acquainted with the secondary Mammalia, and 

 particularly the triassic forms, the latter of which, I anticipate, 

 will be found to have their affinities rather with those of Aus- 

 tralia than with those of Madagascar. I should advert also to 

 the occurrence of the Dodo and its kindred in islands forming 

 but the peaks of a submerged mountain chain connecting Mada- 

 gascar with India. The organization Of these birds was most 

 unfavourable to migration ; and the submergence of a country 

 inhabited by them must necessarily have reduced the birds, first 

 to insulated tracts surrounding the elevated ridges, and lastly to 

 the mountain peaks themselves, which became small islands, as 

 are Mauritius, Bourbon, and Rodriguez, in the midst of the 

 Indian Ocean f. 



• See Lyell's < Principles of Geology/ 1850, p. 610. 



f These islands exhibit the very recent extinction of that volcanic action 

 which has, as I conceive, reduced them from part of the mountain system 

 of that ancient land which once united South Africa and Madagascar to 

 India, into the condition of oceanic islands. See Maillard, Bull. vol. x. 

 p. 499. These islands form, with the Cargados bank and the Chagos, Mal- 

 dive, and Laccadive Archipelagos, a chain of submerged peaks parallel (as 

 is Madagascar) with the eastern coast of Africa, and probably therefore part 

 of the same geological systems which have imparted to the southern half of 

 Africa and to Madagascar their geographical configuration — systems which, 

 in Section 2, I have conjectured to be synchronous with the great known 

 systems therein discussed — that governed the distribution of land during 

 the secondary period, or at least then existing as part of the continents. 



