Hill. — Geology of Haivke's Bay. 471 



boniferous to the Cretaceous period no climatal changes can 

 be proved to have taken place ; whilst froni the Miocene to 

 the Pleistocene (Quaternary) period, during a comparatively 

 short time, a complete alteration took place, and the tem- 

 perature of the Glacial period sank below the present level." 

 Such a statement, coming from so high an authority, should 

 be received with due respect ; but, if we accept the statement 

 as covering the actual facts, it seems to me we shall be led into 

 mazes which go rather to show that the earth in all its de- 

 velopments is rather the product of chance than of a definite 

 law of progress. Was there no change during the thousand 

 centuries that intervened from the Carboniferous to the Cre- 

 taceous period? Denudation proceeded, new life began and 

 ceased to be, and yet we are told that there was no climatal 

 change ! It is not possible to prove by actual experiment 

 that climatal change is constant and ever-active, but the law of 

 change operates, and, as far as we know, has always operated, 

 through everything in nature, and, if it is recognized that 

 heat is passing, and has passed, from the sun and this earth 

 since the time when the latter was a gaseous mass, it needs 

 no proof to show that climatic changes, however small, must 

 have gone on from the Carboniferous to the Cretaceous 

 period, just as they have gone on since the Cretaceous till 

 now. Had there been no climatic change, whence would have 

 come the differentiations in the animal and vegetable king- 

 doms ? With a warm earth, and a warmer sun than now, 

 the earth contrasts in the early periods of life were less marked 

 than now. Every moment since the earth began to be habit- 

 able for the support and maintenance of life, life contrasts 

 have been increasing in the exact proportion to the increase 

 in the differentiations and adaptations in the animal and 

 vegetable worlds. As the heat diminished there were more 

 places adapted to the existence of life, or, in other words, 

 the activities for the maintenance of life increased and ex- 

 tended. This extension brought about adaptation, and so it 

 has been that time, multiplied by climatic change, has pro- 

 duced what we have to-day as the total product of all geo- 

 logical change. 



But do those changes proceed at a more rapid rate to-day 

 than they did in the earlier periods of geological history? 

 I think so. Movements are greater or more rapid between 

 particles of the same substance in exact proportion to their 

 contrasts in the matter of temperature. The mixture of 

 two pints of water, one at 90° of temperature and the 

 other at 92°, would be much slower than the mixture of 

 the same quantity of water at 45° and 100° respectively. 

 The law of exchange comes in here, and the movement in the 

 latter would be more active because the contrasts are greater. 



