328 LIGNITES. 



apprehension, been supposed to prove that origin, and 

 further to justify an analogous theory respecting com- 

 mon stratified coal. But it will be seen that the facts 

 prove nothing on either side; while, the dispute is but 

 one specimen out of many more in geology, founded 

 on bad observation and similar reasoning. 



The lignites in question are often found in the con- 

 glomerates which accompany the trap rocks, com- 

 monly known by the name of Trap tuff. If I need 

 not here describe the varieties of these, I must remark 

 that they often contain rounded materials ; proving 

 some transportation, or motion, previously to their 

 consolidation. It is easy to understand how frag- 

 ments of wood may have been introduced among such 

 materials, when loose, and how the whole mass may 

 have been consolidated together. But this consolida- 

 tion has not resulted from fusion, or from any high 

 degree of heat ; as the very fusible sand in them 

 could not have retained its loose texture in such a case. 

 Although covered therefore by crystalline traps, as 

 they often are, the included lignites have escaped com- 

 bustion under their protection ; while the error of one 

 party has been, not to see what the real situation of 

 the lignite was, and, of the opposed one, to suppose 

 the tufo a rock of fusion ; ever unable to see but one 

 cause for every thing, and that cause, fire. This fact, 

 therefore, does not prove that the solid traps have not 

 been in fusion, but merely that the tufas have not 

 been so formed; of which indeed, there is sufficient 

 other evidence. But, for the other party, it does not 

 prove that the wood has been bituminized by fire ; 

 from the action of which, like the surrounding mate- 

 rials, it has been exempted ; while chemical "reasons 

 will hereafter be adduced to show that vegetable mat- 

 ter is not bituminized by the action of fire alone. 



In other cases, the lignites of trap occur in veins or 



