FROM THE ROCKY MOUNTAINS. 



J51 



of the wood. The lower surface of the fragment offers an almost 

 clean face, directed obliquely downwards across the fibres of the wood. 

 This face, though approximately plane, presents a succession of in- 

 equalities, in the form of slight steps or ledges, which run i^arallel 

 with the successive concentric rings of the wood. These ledges cross 

 the lower face from side to side, and are slightly deeper on that 

 margin of this surface, which appears to have been directed towards 

 the interior of the tree. 



When we look at this fragment of wood as a whole, and endeavour 

 to assign a probable cause for its very remarkable shape, it is difficult 

 to avoid the conclusion that we have to deal here with a veritable 

 fossil chip, cut from one of these ancient trees before silicification took 

 place, and probably whilst the tree was in an erect position. At 

 first sight this may appear a very bold conclusion to arrive at, but it 

 will be shown that this hypothesis will explain all the peculiar 

 appearances presented by tlie fragment, whilst these appearances can- 

 not be accounted for by any other conjecture which would have any 

 likelihood in its favour. In the fii'st place, the upper and lower sur- 

 faces of the fragment are directed across the fibres of the wood, and 

 have, both of them, the character of clean-cut sux'faces — the one curved, 

 the other approximately flat. It is easy, of course, to find specimens 

 of various fibrous minerals, or even of certain rocks, which assvime a 

 somewhat similar shape owing to the action of jointing. Jointing, 

 however, so far as we are aware, could not possibly be induced in the 

 erect trunks of silicified trees, which have not been buried beneath 

 the surface of the earth, nor have been exposed to any of those 

 agencies by which joints are usually believed to be produced. In the 

 absence of jointing as a ]30ssible agency, we are compelled to conclude 

 that the upper and lower surfaces of the fragment have been produced 

 artificially, by some external force; and we are obliged to believe that 

 the force producing them must have acted upon the wood at a time 

 prior to its silicification. We know of no agent capable of producing 

 similar surfaces in wood save man with the aid of tools ; for animals, 

 such as the beaver, which gnaw wood, produce appearances of a 

 totally difi'erent description. 



In the second place, the general appearance of the fragment is pre- 

 cisely that of an ordinary chip cut with an axe from any soft-wood 

 tree. It might be exactly paralleled by dozens of examples which 

 might .be picked up in any locality where trees are being felled on an 

 extensive scale. Indeed, it so closely resembles an ordinary chip that 



