1865.] 



61 



[Lesley. 



higher horizons is shown in Fig. 12. The 

 Venango oil rocks run up nearly a thousand 

 feet over the level of Lake Erie ; the black 

 slates and corniferous limestone of the Canada 

 oil come up from below the bottom of the lake 

 to the north. Wells at Erie strike the oil at 

 900 feet. 



But in Kentucky the black slates of the 

 Canadian oil region underlie the Knobstone 

 formation, and are, therefore, as I have shown, 

 only from 650 to 950 feet beneath the Con- 

 glomerate in the bed of Paint Creek. 



How far this black slate formation has sup- 

 plied the Knobstone above it with petroleum, 

 is a question that our science is not at present 

 qualified to answer. But that it is a dis- 

 tinct horizon of oil every one grants. It has 

 yielded copiously in Canada. Several wells, 

 in Middle Kentucky, sunk in it, have yielded 

 a constant flow.* It is in fact a great deposit 

 of mud, charged with carbon to such extent 

 that many of its layers will burn like coal, 

 and even thin beds of true coal exist in it 

 here and there. These are of course the re- 

 mains of vegetation. But that they have fur- 

 nished all the 5, 10, or 15 per cent, of carbon 

 which we find in the formation, is doubtful, in 

 view of the early age in which it was depo- 

 sited, the abundance of animal life in the 

 limestones under it and in some of its own 

 layers, and the peculiar quality of the Canada 

 oil which proceeds from it or from the lime- 

 stone under it. 



Fis. 12. 



* 111 Estill County, one well was ruined by the force 

 of ga.s. Another, bored by S. T. Vaughn, 405 feet, 

 went through soil 15 feet, black slate 100, light clay 

 limestone 100, gray limestone 190 feet, when the auger 

 dropped, salt water gushed out, and soon gave place to 

 the present constant stream of oil. K. E., iv, p. 472. 



