670 J. A. BOWNOCKER PETROLEUM IN OHIO AND INDIANA 



tion followed. In 1896 the output from the Trenton field in Ohio at- 

 tained its maximum and exceeded 25,250,000 barrels. The maximum 

 production was not reached in Indiana until 1904, when the yield was 

 in excess of 11,300,000 barrels. How far these States have passed the 

 zenith of their production from this rock is shown h^ the fact that in 

 1914 the yield from Ohio was only 3,700,000 barrels and from Indiana 

 1,300,000. The drill, however, is at work in both States and in 1915 

 1,262 wells were sunk, of which nearly 1,100 were rated as producers. 

 The initial yield of these, however, was small and more old wells were 

 abandoned than new producers secured. Doubtless the proportion of 

 abandoned wells will increase from year to year, and yet the end of the 

 Trenton field is not in sight. The magnitude of the drilling is shown by 

 Barrett's statement that 30,000 Trenton wells have been drilled in 

 Indiana, and doubtless the number in Ohio is much larger. The pro- 

 ductive territory extends in a disconnected manner from Lake Erie, east 

 of Toledo, southwest like an arc of a circle to Marion, Indiana, a distance 

 of approximately 150 miles. In width the range is great; in places it 

 is sufficient for only a few rows of wells, while elsewhere it may be 20 

 miles. 



The rock succession is shown by the following well records :^ 



Ohio Indiana 



Thickness Thickness 



Feet Feet 



Drift 8 Drift 50 



Niagara limestone 167 Niagara limestone 153 



Niagara shale and Clinton Hudson River limestone 451 



limestone 108 Utica shale 300 



Medina shale • . 47 Trenton limestone at 954 



Hudson River shale and 



limestone 462 



Utica shale 300 



Trenton limestone at 1,092 



So regular are the formations that these well records can be duplicated 

 by the thousand, though there is considerable variation in the depth of 

 wells due to their position with reference to anticlines. In the Ohio 

 fields the depth to the Trenton usually ranges from 1,000 to 1,500 feet, 

 but in Indiana the depth is more uniform and, according to W. S. Blatch- 

 ley, averages 1,000 feet. The principal "pay rock" usually lies within 50 

 feet of the top of the Trenton, and in early days in the Ohio part of the 

 field it was a general belief among drillers that unless oil was found by 



" Edward Orton : Geol. Survey of Ohio, vol. vi, p. 112. 

 W. S. Blatchley : Indiana Dept. of Geol. and Nat. Res., 1897, p. 68. 



