160 M. H. JOHNSON ON SILICIFIED STRUCTURE IN PYR1TIZED WOOD. 



In silicified wood, using the term as it is generally understood, 

 the silicified woody structure, instead of being filled in with pyrites, 

 is filled in with silica. If a slice of such wood be taken and 

 stained with acetate of ros aniline, it will be found that it is the 

 coll wall, the representative of the wood itself, that takes the 

 colour, while the filling in remains uncoloured. In like manner 

 flints, stained in the same way, show the structure of the organism 

 coloured, while the filling in remains uncoloured, or compara- 

 tively so. 



I offer these notes in the hope that they may help in some 

 measure to elucidate the subject of silicification. 



