Lesley.] ^Q [April. 



the base of this upper member as it does from the base of the 

 lower member. This is at an elevation of at least 150 feet 

 above the creek. 



So, also, under the numerous cascades which the top plate 

 of the upper member of XII makes, for miles up the vallej, 

 there are similar exudations, as if the top member was charged, 

 like the bottom member, with petroleum. 



Lower Horizons of Petroleum. — Under the country of 

 Paint Creek and the Licking waters lie the rocks of the 

 Devonian System, the upper part of which is the well-estab- 

 lished horizon of the IsT. W. Pennsylvania oil, and the lower 

 part of which is the equally well-known horizon of the Canada 

 and Michigan State oil. If we can get, therefore, the thick- 

 ness of measures between the bottom of the Conglomerate, 

 No. XII, and the top of the Devonian Formation, and also 

 the thickness of the Devonian Formation itself, we can ap- 

 proximate to the calculations of the normal depth of oil wells, 

 if bored to reach, first, the Pennsylvania oil, and secondly, 

 the oil of Canada. 



This, then, is the first question : — How deep should the 

 Lyon Well, or the Hinckley Well, or the Spradley Well, or 

 any other well starting from the bottom of the Conglome- 

 rate, descend, to strike the upper face of the Devonian Sand- 

 stone ; and how much deeper must it continue to go to reach 

 the Blue Limestone on which the Devonian System rests ? 

 When this first question is answered, it does not follow that 

 the oil will be struck at precisely those places in the Devo- 

 nian System at Avhich it is struck in Pennsylvania, Virginia, 

 or Canada ; for that Avould depend on the continuance, over 

 immense distances, of certain individual oil-bearing rock 

 members of that system. Thirdly, The quantity of oil at 

 any such level will be a local peculiarity, dependent origi- 

 nally on the local abundance of organic matter, both ani- 

 mal and vegetable ; and, secondarily, on the local thickness, 

 coarseness, and general fractured condition of the oil-bearing 

 rock. 



To answer this question, it is necessary to state the order 

 of the formations, as follows, descending: — 



