VI PREFACE. 



nothing of the toil that first laid it on the quaking morass, and as little 

 does he care ; while he is enraged at the casual rut. But though such 

 a System should teach nothing, it would be valuable by the display of 

 its very defects. No chasm can be filled till it is known: while thus 

 are errors and blanks classed with the nearest truths, so as (o indicate 

 the way by which they are to be corrected and supplied. All sciences 

 commence with error; and he who waits for the hour of perfection, 

 suppressing what he knows, because too proud or too timid to confess 

 a pardonable ignorance, is the 2,x^ aa " rLKOS WHO w i^ no ^ enter the water 

 till he can swim. Nor will the day of truth ever arrive, if they who 

 can add to the stock of knowledge confine it within themselves. 



Be the result what it may, it is my duty to say, that it rests, with 

 some exceptions, on my own observations, confirming those of others, 

 when not original. Observers may differ ; but Nature is always the 

 same. And it was my duty to confirm my references to authorities, by 

 applying to the great source of all Authority, wherever this was pos- 

 sible. Thence have I quoted, more in confirmation than for any other 

 purpose: never trusting, even to names of reputed weight, when the 

 facts were contradictory to those which I had verified, or to just 

 analogies, or to the principles of the collateral sciences: assured that 

 Nature cannot differ from herself, nor one truth oppose another. These 

 are the real grounds on which the validity of authorities must be tried : 

 and hence perhaps have I quoted fewer than might have been expected ; 

 yet, I think, enough ; since an indiscriminate or careless reliance on 

 them is a most perilous foundation for a work on this Science. An 

 ambitious multiplicity of writers, sectarianism, and hypothesis, must 

 ever be the source of bad observations, if not also of gratuitous asser- 

 tions: while an established phraseology gilds all this with the aspect 

 of knowledge. No system of geology can yet be compiled from the 

 works of others ; though often attempted. Kirwan has revelled in 

 authorities to prove how much we knew: a later writer has proved, 

 from the same authorities, that we know nothing. Nor does any one 

 who even aspires to the name of philosopher, suffer another to reason 

 for him; as, never yet was any system in philosophy founded on the 

 eyes or the opinions of others. 



Geologists have been acused of founding theories upon single and 

 favoured districts; yet have I drawn my chief illustrations from Britain. 

 It is true: but there is no resemblance in the applications: as I can 



