OF THE ORGANIC FOSSILS. 415 



lias been : and this explanation of the real nature of 

 amber, so long disputed, is confirmed by the semibi- 

 tuminization of similar resins in later strata, accom- 

 panying, similarly, semibituminized wood, as I for- 

 merly explained in different papers on these subjects. 

 The existing resins, equally including insects, resemble 

 these fossil substances so much, as to be constantly 

 sold for amber, and not always from fraud, but from 

 ignorance: but the test is easy, as I have shown in a 

 paper on this subject in one of the journals. 



Of the Rocks in which organic Fossils occur. 



This forms an important question in geology : they 

 abound in some, and are absent from others ; while it 

 will be anticipated that they should occur in the stra- 

 tified, and be excluded from the unstratified rocks. 

 And such is the fact. No one has imagined that they 

 could occur in granite ; but they who desired to make 

 the trap rocks of aqueous origin, have pretended to 

 find them in those. It is necessary to show what the 

 error and the truth are. Nor can they be expected in 

 Serpentine or in Diallage rock; for I have proved 

 that these also are rocks of fusion. 



They may exist in the tufas of this family, because 

 these are conglomerates, often transported, and often 

 aqueous: It is the very case of Pompeii in another 

 form ; and thus is bituminized wood found under and 

 in the solid trap of the Western Islands of Scotland ; 

 but when in the latter case, it is found in the midst of 

 entangled tufas. When said to have occurred in 

 basalt, this is the error of ignorance : the indurated 

 shale, or Lydian Stone, beneath it, has been mistaken 

 for that substance, as I have proved. If a shell should 

 even be found in a real basalt, as has been said to 

 have occurred, this is possible, because basaltic veins 



