A Forest Fire at St. John '3000 Years ago. 215 



this stage (two feet below the surface) was a purely vege- 

 table deposit. 



From the fact that both at Torryburn and Eockwood 

 there is a charcoal deposit at about the same horizon in 

 the Eecent deposits, it appears reasonable to infer that 

 they had probably a common origin, and that this was a 

 forest fire, which extended over an area of at least some 

 miles in the vicinity of St. John. The question arises — if 

 there was such a fire at the time indicated, how was it set ? 



It has been suggested that such fires arise from the heat 

 developed by a lightning stroke. But while buildings are 

 often destroyed in this way, it would seem that growing 

 trees, which are often struck, seldom take fire. This may 

 be attributed to the dampness of the trunk and foliage, 

 which rapidly conducts the electricity away ; and then if 

 a fire should originate from this cause, it stands a f^ood 

 chance of being extinguished by the rain which usually 

 accompanies a thunder storm. 



I have seen it stated that in the South of France forest 

 fires have been known to originate from the drops of bal- 

 sam which exude from pine trees, these drops forming 

 natural lenses which concentrate the rays of the sun and 

 lead to ignition of the wood through the resinous vapors 

 that escape the balsam or gum. 



It appears to the writer that neither of these causes 

 has been active in this region in Eecent Geological Time 

 in setting fire to forests. For we have in the Eockwood 

 bog a record of the physical events of this kind for a 

 period reaching back for from 6000 to 9000 years. The 

 Eockwood deposit has been carefully examined inch by 

 inch, and layer by layer, from the summit to the bottom, 

 and this in three different places, but no charcoal frag- 

 ments have been met with, except at the one level of two 

 feet below the surface. If the fire had been due to physi- 

 cal causes there is good reason to think that such fires 

 would have recurred at intervals, from the time that the 



