SIR CHARLES LYELL 207 



the speculations of some writers, there have been in the past history 

 of the planet alternate periods of tranquility and convulsion, the 

 former enduring for ages, and resembling the state of things now 

 experienced by man ; the other brief, transient, and paroxysmal, giv- 

 ing 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 inanimate world must give rise to such 

 breaks in the sequence, and such unconformability of stratified rocks, 

 as are usually 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 ob- 

 served 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 sci- 

 ence to supply some part of the assumed course of nature hypo- 

 thetically; but if so, this must be done without any violation of 

 probability, and always consistently with the analogy of what is known 

 both of the past and present economy of our system. Although the 

 discussion of so comprehensive a subject must carry the beginner far 

 beyond his depth, it will also, it is hoped, stimulate his curiosity, and 

 prepare him to read some elementary treatises on geology with advan- 

 tage, and teach him the bearing on that science of the changes now in 

 progress on the earth. At the same time it may enable him the 

 better to understand the intimate connection between the Second and 

 Third Books of this work, one of which is occupied with the changes 



