395 



occur, in petrified ligneous substances. The instances which have 

 been given of any fossil substances which had derived their form 

 from the labours of the inhabitants of the world, at any distant 

 period, are remarkably few, and do, indeed, all appear under cir- 

 cumstances which render the actual existence of such petrifactions 

 highly problematical. 



The substances which have been most frequently mentioned, as 

 being of this description, are those which bear the form of logs, 

 billets, posts, and planks. But, surely, when it is considered, that 

 a rude resemblance may have been frequently sufficient to have 

 given rise to this opinion, and that wood, long exposed to the 

 weather, to alternate sunshine and wet, to agitation in water, and 

 afterwards buried by some violent convulsion, must be broken into 

 a great variety of forms, it is not at all improbable, that it should, 

 in some instances, assume an appearance, that may lead to the 

 suspicion of its having been subjected to the operations of art. 

 The same observation must apply to many of those substances 

 which have been supposed to have been stakes, posts, and piles, 

 which have been driven in the beds of rivers, &c. Of this descrip- 

 tion are the pieces of wood which have been frequently dragged 

 up from the bottom of the Thames, and which have been supposed 

 to have been placed there by the soldiers of Julius Caesar. One of 

 these was in the possession of the late Duchess of Portland, and 

 was purchased at her sale, for nine guineas, by the late John Hun- 

 ter, Esq. and is in the matchless museum, which, by the death of 

 that gentleman, is now in possession of the Royal College of Sur- 

 geons of this city. An examination of thifrbody tends to confirm 

 my suspicion, that substances of this kind do not owe any thing of 

 their forms to the labours of the Roman soldiers. This piece of 

 wood, about three feet in length, the surface of which is broken 

 into flakes, by drying, has exactly the colour, and general appear- 

 ance, of bituminous wood. Now from the observations, already 



