Lesley.] 5g [April. 



The proportion which the oil bears to the water in the gravel 

 is unknown, but must be far greater than in the 30 feet of 

 sandrock (taking one of the Venango oil rocks as a base 

 of calculation) at the top of which the gravel lies ; for the 

 oil will settle in these top layers of gravel, while the water 

 remains in the body and lower layers of the sandrock. If 

 the proportion in all bel to 100 (for the sake of the calcu- 

 lation), the proportion in the gravel may be 1 to 10, and in 

 the few inches at the extreme top, even 10 to 1. If we should 

 suppose only the uppermost four inches of the whole forma- 

 tion charged with pure oil, that would give an absolute layer 

 of oil one inch thick underspreading the whole cou^ntry as far 

 as the sandrock extends, or about 4000 millions of square 

 inches under every square mile, or, in other words, 17^ mil- 

 lions of gallons = 551,706 barrels. Each smtdrock should 

 be able to supply from each square mile of its area, the whole 

 present oil produce of the United States for ninety days be- 

 fore it is exhausted, and that without any reference to the 

 accumulation of petroleum in fissures. 



Let us carry the calculation a little fiMrther, by taking now 

 the fissures into consideration. 



The Paint Creek country is one of the most undisturbed 

 on earth. But the drying and hardening to which they are 

 subjected through geological ages crack all rocks ; and neces- 

 sarily in three directions. Two of these directions are always 

 and necessarily nearly vertical, one of them again, being the 

 direction of the primary or master system, going down 

 straighter and deeper, and giving origin oftener to large 

 fissures and downthrows.* 



* The downthrow at Davis's, the petroleum vein on Hughes' Kiver, 

 and othci- faults and fissures of magnitude in this part of the Bituminous 

 Coal area, all belong to the same almost east and west system of cleav- 

 age-planes observable in the Alleghany River country. 



In one great fissure (4 feet wide) of this east and west system on 

 Hughes' Eiver, the Devonian petroleum which underlies the Kanawha 

 country (precisely as it undei'lies the Paint Creek country) has collected 

 itself and hardened into asphalt, before the Kanawha valleys were 

 scoured out. There stands this vertical, east and west running vein of 

 solid petroleum, an evidence both of the abundance and of the antiquity 



