32 E. Petitot on the Athabasca District. 



little cones of whitened and scorified earth. Beyond these places, 

 indications of active and extinct igneous action are only found on 

 the right bank of the Athabasca and Mackenzie system, reappear- 

 ing all along this immense fluvial artery with an intermittent 

 activity and inaction difficult to explain. In some places these 

 " boucanes," after having vented fire and smoke for decades, en- 

 tirely disappear, only to show themselves without apparent cause 

 elsewhere. 



Traces of the subterranean bituminous veins that keep up these 

 fires can be followed to the shores of the Arctic Ocean, in the cliffs 

 of Franklin Bay and Cape Bathurst, where Sir John Richardson 

 took them to be active volcanoes. 



These ' ; boucanes " are usually found on the line of imperfect 

 coal, i.e.. of deposits of lignite incompletely carbonised, and con- 

 sequently unfit for the forge or fuel. They are so along the 

 Boucanes River, one of the affluents of the Peace River, as well 

 as above Fort Norman on the Lower Mackenzie ; but here there is 

 no outer trace of coal or lignite, though it is probable that there 

 are subterranean veins of those substances, and that the jxheno- 

 mena mentioned are owing to the protocarbonated hydrogen of the 

 coal deposits. Nevertheless (although fire-damp explodes on contact 

 with oxygen, ns is often found at the beginning of winter in some 

 of the lakes of the north-west), the capability of spontaneous 

 illumination which Richardson attributes to the identical exhala- 

 tions of Fort Norman, has not been found to exist in this gas. 

 It is impossible to attribute to the Indians the extinction of the 

 fires of bituminous schists in the Athabasca-Mackenzie system. 

 Their ignition is intermittent, without apparent cause, and 

 unstable. It is, moreover, accompanied by a strong smell of 

 petroleum, whilst hydrogen is inodorous. But the carburets of 

 hydrogen, of which petroleum is composed, do not make it, any 

 more than they do fire-damp, spontaneously inflammable, even on 

 contact with air, — in spite of received popular opinion. We 

 must, therefore, consider them as one of the effects of igneous 

 action, materially connected with the fire of the volcanoes ; for the 

 Bnucanes occur under similar conditions to the vents of these sub- 

 terranean fires, being found on the river banks, on intermediary 

 strata inclosing schist, bitumen, lignites, thermal sulphurous or 

 saline waters, rock-salt, &c. 



