hy Dr. T. Sierry Hunt. 249 



part of the township has hitherto been sent to Boston, though 

 refining works are now being erected at the wells. The process 

 of refining consists in rectifying by repeated distillations, by which 

 the oil is separated into a heavier part employed for lubricating 

 machinery, and a lighter oil, which after being purified and deod- 

 orized by a peculiar treatment with sulphuric acid, is fit for 

 burning in lamps. 



These wells occur along the line of a low broad anticlinal axis 

 which runs nearly east and west through the western peninsula 

 of Canada, and brings to the surface in Enniskillen the shales 

 and limestones of the Hamilton group, which are there covered 

 with a few feet of clay. The oil doubtless rises from the Corni- 

 ferous limestone, which as we have seen contains petroleum ; this 

 being lighter than the water which permeates at the same time the 

 porous strata, rises to the higher portion of the formation, which is 

 the crest of the anticlinal axis, where the petroleum of a consi- 

 derable area accumulates and slowly finds its way to the surface 

 through vertical fissures in the overlying Hamilton shales, giving 

 rise to the oil springs of the region. The oil is met with at 

 various depths ; in some cases an abundant supply is obtained at 

 forty feet, while near by it is only met with at three or four times 

 thatdepth,and sometimes only in small quantities. Everything points 

 to the existence of separate fissures communicating with a deep- 

 seated source. At Kelly's wells however,it would appear that a reser - 

 voir has been formed much nearer the surface, where in a bed of 

 gravel and boulders, underlying the superficial clays, the oil rising 

 from the rocks beneath has accumulated. The inflammable gas 

 which issues from the wells is not necessarily connected with the 

 petroleum, inasmuch as it is an almost constant product of the 

 decomposition of organic matters, and is copiously evolved from 

 rocks which are destitute of bitumen. It is similar to the gas 

 of marshes and to the fire damp of coal mines. A curious cir- 

 cumstance is however noticed by Mr» Robb ; the gas which accu- 

 mulates in the oil pits, becomes charged with vapors which pro- 

 duces upon the workmen a sorv of intoxication like nitrous oxyd.* 

 This is not surprising when we remember that volatile hydrocar- 



* Mr. Charles Robb, C.E., has published in the Canadian Journal for 

 July an interesting paper on the oil wells of Enniskillen, to which, as also 

 to a paper by Prof. E. B. Andrews of Ohio, in Silliman's Journal for July 

 I am indebted for several facts. 



