FROM THE TERTIARY DEPOSITS OF TASMANIA. 349 



must take place on the surface to alter the relative positions of the 

 poles with regard to the surface of the earth. Because there were 

 proofs of warmer climate having existed in Miocene times in Green- 

 land, near the one pole, aud in New Zealand near the other, there 

 was no need to suppose that belts of warmer temperature had ex- 

 tended nearer the poles than at present, for the same sliding of the 

 crust that brought Greenland nearer the equator would also bring 

 New Zealand nearer the tropics, both being on nearly the same 

 meridian, but on opposite sides of the globe. The subject was one 

 that deserved the attention of geologists, as it lay at the root of 

 many important questions affecting the past history of the earth. 



Professor Hughes believed implicitly what the astronomers told 

 him must be ; and if observations on the distribution of life neces- 

 sitated any thing more than such alterations of climate as could be 

 accounted for by geographical changes and modification and adapta- 

 bility in the forms of life, he would prefer to leave it as one of the 

 many things he could not explain, than accept an explanation in- 

 consistent with accepted astronomical theories. If, as explained by 

 Sir John Herschel, the transference of large masses from one part of 

 the earth's surface to another would disturb the equilibrium, we 

 must remember that this action would be mostly compensative ; and 

 if the cumulative effect of many such disturbances might be a partial 

 readjustment of the mass, we must regard such movements only as 

 a tendency to keep the whole mass and its axis of rotation as it was 

 in spite of the transference of portions from one place to another 

 by denudation. Moreover he disputed the data on which the views 

 advocated by both the present and the late President were founded. 

 He asked whether we should say that the climate of the period of 

 our older river-gravels was that of Egypt or of Northern Siberia, 

 seeing that the Corbicula fluminalis and Unio littoralis were now 

 found only much further south ; while the hairy elephant and rein- 

 deer, which had once lived with them, were now held to prove an 

 arctic climate. When we know that flowering plants and ever- 

 greens now live in Alpine regions, where they are buried in total 

 darkness under snow for four months, shall we say that the absence 

 of light would render it impossible for evergreens and flowers to 

 have flourished where the arctic winter-night is four months long, 

 even though we could account for a milder climate by geographical 

 changes. 



Mr. Woodward remarked that as it was not merely a question of 

 one fauna and flora, Mr. Hughes's statements must be received with 

 caution. There were evidences in northern latitudes, not only of a 

 Miocene, but also of a Carboniferous, a Jurassic, and a Cretaceous flora. 

 Xor was it a question merely of lowly organized plants which would 

 be more likely to withstand the climate ; for Prof. Nordenskiold had 

 found tree- trunks standing erect in the soil in which they grew, and 

 it was impossible for them to have grown in a climate so rigorous as 

 now exists at that latitude. If the geologists are wrong in the con- 

 clusions they have drawn from these facts, let the astronomers show 



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