ORIGIN OF THE ROCK PRESSURE OF NATURAL GAS IN 
THE TRENTON LIMESTONE OF OHIO AND INDIANA.* 
By EDWARD ORTON. 
THE IMPORTANCE OF THE PRODUCT. 
Natural gas derived from the Trenton limestone has supplied during 
the last year and is now supplying all the fuel and a considerable part 
of the artificial h¢ght that is used by at least four hundred thousand 
people in northwestern Ohio and in central Indiana. Within the same 
limits it is the basis of a varied line of manufactures, the annual prod- 
uct of which will make an aggregate of many millions of dollars. More 
than forty glass furnaces, not one of them three years old, are now in 
very successful operation within the territory named, while iron and 
steel mills, potteries, and brick works, and a long list of factories in 
which cheap power is a desideratum, have been built up on all sides 
with wonderful rapidity. 
The largest gas production of the Trenton limestone that has yet 
been reached is to be credited to the present year. A well, drilled early 
last summer at Stuartsville, 6 miles north of Findlay, produced through 
the casing, a pipe 53 inches in diameter, 28,000,000 cubic feet of gas 
every twenty-four hours. There are but few wells in any field that ex- 
ceed these figures. Most of the wells so reported have been estimated, 
not measured. 
An equally astonishing advance has been made in the oil production 
of this rock within four counties of northwestern Ohio. Single wells 
drilled during the last year have begun their production at a rate of 
10,000 barrels per day, and more than 200,000 barrels of total produe- 
tion are already to be credited to single wells of the new field, while 
a considerable number have passed the 100,000-barrel mark. 
THE ROCK PRESSURE. 
The rock pressure of the gas is a vital factor in all this production. 
To its energy is due the propulsion of the volatile fuel from the wells 
where it is released, through 20, 30,50 miles of buried pipes, to the 
*Read before the Geological Society of America, December 26, 1889. (From the 
Bulletin Geolog. Soc. Amer., March 1, 1890, vol. 1, pp. 87-94.) 
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