824 



/. A. BOWNOCKER 



gas-bearing beds are magnesian. This is shown by the follow- 

 ing analyses : 



It was further found that in some places at least the mag- 

 nesian character of the rock changes rapidly from the surface 

 of the formation down. Thus an analysis of the rock lying 100 

 feet below the top of the Trenton at Bowling Green showed 

 over 88 per cent, of CaC0 3 and less than 7 per cent, of MgC0 3 ; 

 while, as shown above, the upper portion of the same formation 

 has less than 52 per cent, of CaCO s and more than 36 per cent, 

 of MgC0 3 . The magnesian character is important, since it ren- 

 ders the rock porous, thus making it a suitable reservoir for the 

 oil and gas. Outside of the producing territory in Ohio the 

 Trenton loses its magnesian character, the CaCO s composing 

 usually at least 75 per cent, of the formation. 1 



The rock is often highly fossiliferous, and occasionally the 

 pieces brought up by the sand pump are little more than a 

 cemented mass of shells, resembling in this respect the lime- 

 stones of the Hudson River series. Dr. Orton referred the for- 

 mation, as shown in the Findlay well, to the Galena, Trenton 

 proper, and Birdseye divisions. 2 The total thickness of the 

 Trenton in northwestern Ohio is unknown, but it exceeds 780 

 feet. In the southwestern part of the state it is 650 feet, as 

 shown in a well drilled on the McGhee farm in Liberty town- 

 ship, Adams county. This thickness is similar to that reported 

 in Kentucky. 



The relation stratigraphicaliy of the Trenton to the next 

 important producer, the Clinton, is shown in the following 

 records : 



1 Ibid., Vol. VI, pp. 103, 104. 



•Ibid., Vol. VI, p. 116. 



