420 SIR CHARLES LYELL 



the genera, are 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 

 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 framework of the globe we have a chronological 

 chain of natural records, many links of which are wanting: 

 but a careful consideration of all the phenomena 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 uninterrupted series of changes in the animate and in- 

 animate world must give rise to such breaks in the sequence, 

 and such unconformability of stratified rocks, as are usu- 

 ally thought to imply convulsions and catastrophes. It is 

 scarcely necessary to state that the order of events thus 

 assumed to occur, for the sake of illustration, should be in 

 harmony with all the conclusions legitimately drawn by 

 geologists from the structure of the earth, and must be 

 equally in accordance with the changes observed by man to 

 be now going on in the living as well as in the inorganic 

 creation. It may be necessary in the present state of 

 science to supply some part of the assumed course of nature 

 hypothetically ; but if so, this must be done without any 

 violation of probability, and always consistently with the 



