ORIGIN AND DURATION OF PETROLEUM. 275 



have supposed that the animal matter has been distilled, 

 and has thus formed the oil. 



If such a process could be imitated artificially by distill- 

 ing some of the later deposits of similar fossil character 

 this theory would have a better basis, or even if a collection 

 of oysters, mussels, or any other animal matters could by 

 distillation be shown to produce an oil similar to petro- 

 leum. 



The contrary is the case. We may obtain oil from such 

 material, but it is utterly different from any kind of min- 

 eral oil, while, on the other hand, by distilling natural bi- 

 tuminous shales, or canuel coal, or peat, we obtain a crude 

 oil almost identical with natural petroleum, and the little 

 difference between the two is perfectly accounted for by the 

 greater rapidity of our methods of distillation as compared 

 with the slow natural process. "We may go on approximat- 

 ing more and more nearly to the natural petroleum by dis- 

 tilling more and more slowly. As it is, the refined products 

 of the natural and artificial oil which is commercially dis- 

 tilled in Scotland, are scarcely distinguishable some of 

 them are not at all distinguishable the solid paraffin, for 

 example. I now offer my own theory of the origin of oil 

 springs. 



To render this the more intelligible, let us first consider 

 the origin of ordinary water springs. St. Winifred's Well, 

 at Holywell, in Flintshire, maybe taken as an example, not 

 merely on account of its magnitude, but because it is quite 

 typical, and is connected with limestone and sandstone in 

 about the Fame manner as are the petroleum wells of 

 Pennsylvania. 



Here we have a wondrous uprush of water just between 

 the sandstone and mountain limestone rocks, which amounts 

 to above twenty tons per minute, and flows down to the 

 Dee, a small river turning several water-mills. It is cer- 

 tain that all this water is not generated either by the lime- 

 stone or the sandstone from which it issues, nor can it be 

 all "generated " on the spot. The true explanation of its 

 origin is simple enough. 



The mountain limestone underlies the coal measures and 

 crops up obliquely at Holywell; against this oblique subter- 



