606 THE OIL-FIELDS OF EASTERN CANADA. — ELLS. 



now found by boring, and have asce'nded gradually till tbey 

 have met the porous dolomite of Devonian age in which they 

 now seem to occur. They were held in place by the overlying 

 cover of grey shales which succeeds the limestone, and which by 

 the drillers is usually called " soapstone ". and by this im- 

 pervious cover, under great pressure, are hermetically sealed 

 till the overlying rock is Dierced, when they make their escape 

 to the surface with tremendous force. The strata throughout 

 the Ontario oil district lie in an almost horizontal position or in 

 gentle anticlines so low that the dip of the beds is scarcely 

 perceptible to ordinary measurements. 



To go into elaborate details as to causes and effects \\ould, 

 however, swell the present paper to too great lengths. They 

 can be well studied by reference to the excellent report by Dr. 

 Orton on the " Occurrence of Petroleum, etc., in Kentucky," 

 and in other bulletins of a special nature relating to the subject. 



^Yhile rock-oil and natural gas are widely distributed 

 throughout the Dominion of Canada, and while attempts to 

 work many of these deposits have been made at a number of 

 places from time to time, it is to be regretted that in many cases 

 such efforts ha^■e been usually attended with a lack of fruitful 

 results. Much of this unnecessary expenditure could have been 

 avoided had due attention been given to the geological features 

 of the several areas which have lieen tested. 



In so far as boring investigations for oil are concerned in 

 Canada it must be confessed that up to the present the original 

 field in south-west Ontario has been the o'nly one that has given 

 satisfactory results. Tt is, however, confidently expected that 

 at some future time i)ortions of the great Cretaceous rvlain east 

 of the Rocky mountains, in which large suvwilies of natural gas 

 are now being developed, will be found to be also oil-producing ; 

 but this is still matter for future investigation. It may, how- 

 ever, be stated that the Pierre shales, in which the oils of the 

 Florence basin in Colorado occur, have an extensive develop- 

 ment in the Canadian north-west. 



