114 ORIGIN" OF PENNSYLVANIA PETROLEUM. [Feb. 5, 



the floor of the basin in which the measures of these periods were 

 deposited. The uplift which forms the Appalachian chain occurred 

 at the close of the Carboniferous period. This was due directly to 

 heat action. It is, therefore, at least suggested that the petroleums 

 of Pennsylvania owe their origin to the effect of this heat upon the 

 underlying limestones and shales of the Silurian age. The theory 

 is, that the same force which caused the Appalachian chain to 

 uplift, passing through the limestones and shales of the Silurian age 

 at a modified temperature, distilled the oil already contained in 

 these shales and conglomerate sands of the Devonian age, 

 where it was condensed and filtered and found its home in the open, 

 porous conglomerates which characterize the Catskill, Portage and 

 Chemung periods of the Devonian age. 



^' There are many reasons why this theory seems to be more satis- 

 factory, to me, than any of the others. In the first place, the pecu- 

 liar characteristic of the Silurian oil is its well-known sulphur com- 

 pound, which for many years presented almost insurmountable 

 difficulty to the refiner. The low specific gravity is its second 

 characteristic quality, and a uniform quality marks it everywhere. 

 In the oils of the Pennsylvania region and the Devonian horizon 

 we have a range of color from light amber to black, a higher spe- 

 cific gravity and almost entire freedom from sulphur compounds. 



'' In addition to what has been said with reference to the Silurian 

 period, it may also be added that at its top lies the Corniferous 

 limestone, which is the source of the petroleum of western Canada. 

 This limestone has been reached by the drill in Pennsylvania in the 

 well at Erie and at the Conway well, which, piercing the Venango- 

 Butler group, reaches the Corniferous limestone. In neither case 

 was any trace of oil discovered in the Canadian measure. In addi- 

 tion to the varieties of color and specific gravity, together with the 

 freedom from sulphur which characterizes the Pennsylvania petro- 

 leums and indicates the process of filtering, it is also extremely 

 doubtful whether the measures of the Devonian age and particularly 

 those in which the Pennsylvania petroleums are deposited, ever con- 

 tained any life which could have given rise to the petroleum. It is 

 generally conceded that the great volume of the oil which is found 

 in the Trenton and Clinton limestones is due to chemical action 

 upon the organic life of that period. The experience which has 

 been the result of many years of drilling in Pennsylvania has failed 

 to discover any evidence of organic life in the period in which the 



