PREFACE. XXXI 



for himself any accurate ideas on that which is 

 known by experienced geologists, however dif- 

 ferently it may be held in estimation by different 

 persons ; since it is either traditional, or scattered 

 through various miscellaneous writings. But 

 even could this knowledge have been found else- 

 where, it would not have been the less necessary 

 here ; although it might then have been stated in a 

 more condensed manner. But it is the fate of all 

 first attempts to be superfluous, perhaps diffuse ; 

 since the eventual utility of that which is new 

 cannot always be foreseen. Condensation is the 

 result of time, and of that experience which rejects 

 what is no longer essential. Ifj in studying to 

 render his labours useful and intelligible to those 

 for whose use it was designed, the author has pro- 

 duced a work far more bulky than he had at first 

 contemplated, it must be recollected that it is easy 

 to eradicate the feebler plants of the forest when 

 the more vigorous trees have rooted themselves 

 in the soil. 



