Masterpieces of Science 



different. These violations of continuity are so 

 common as to constitute in most regions the rule 

 rather than the exception, and they have been 

 considered by many geologists as conclusive in 

 favour of sudden revolutions in t the inanimate 

 and animate world. We have already seen that 

 according to the speculations of some writers 

 there have been in the past history of the planet 

 alternate periods of tranquillity and convulsion, 

 the former enduring for ages and resembling the 

 state of things now experienced by man ; the other 

 brief, transient and paroxysmal, giving rise to 

 new mountains, seas and valleys, annihilating 

 one set of organic beings and ushering in the 

 creation of another. 



It will be the object of the present chapter to 

 demonstrate that these theoretical views are not 

 borne out by a fair interpretation of geological 

 monuments. It is true that in the solid frame- 

 work of the globe we have a chronological chain 

 of natural records, many links of which are want- 

 ing: but a careful consideration of all the phe- 

 nomena leads to the opinion that the series was 

 originally defective- that it has been rendered 

 still more so by time that a great part of what 

 remains is inaccessible to man, and even of that 

 fraction which is accessible nine-tenths or more 

 are to this day unexplored. 



The readiest way, perhaps, of persuading the 



reader that we may dispense with great and 



sudden revolutions in the geological order of 



events is by showing him how a regular and un- 



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