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many of the occult phenomena of the present day ; and 

 we may be equally satisfied that this cannot by any 

 possibility be attempted without the assistance of geo- 

 logy. Let us therefore glance hastily at a few of those 

 more undeniable convulsions which we are aware have, 

 at various epochs, taken place ; and endeavour to catch 

 a glimpse of how, in the common course of things, that 

 portion of the insect world would be affected which was 

 exposed to their influence. 



First and foremost, perhaps, in importance, of all the 

 changes which it is self-evident have happened, may be 

 mentioned subsidence. Including, as it does, both the 

 general lowering of some countries, and the actual isola- 

 tion of others, there are, I believe, no physical crises to 

 which we could point, through the instrumentality of 

 which the very existence of the insect races (not to 

 allude to their diffusion) has been, by the nature of the 

 case, more seriously interfered with. We know that 

 there are certain species of an alpine and boreal cha- 

 racter, which cannot live except in a climate of low tem- 

 perature, guaranteed to them either by elevation in one 

 land, or by a higher latitude in another : and let us 

 picture the consequences of the gradual sinking of a 

 mountain chain, even to a small extent, the summits of 

 which only just afforded the conditions of atmosphere 

 necessary for the continuance of creatures like these. 

 Now this is an example by no means far-fetched, and 

 such as must have occurred in instances innumerable. 

 But, what would be the many results of a diminution in 



