Orion — Book Pressun oft/u Natural 225 



tested l>y the answer to the question whether similar phenom- 

 ena occur outside oi the area of glaciation. A negative answer 

 would form a Btrong support to Mi-. Gilbert's theory; and an 

 affirmative would compel search for a more general cause or a 

 distinct one. 

 Lawrence University. 



Art. XXX. — On the Origin of tl>< Rock Pressure of the 

 Natural f tfu Tn nton Limestone of <)fii<> and 



Indiana; by Edward Orton. 



DURING the last five years, there has been developed within 

 six counties of northwestern Ohio, the most important single 

 source of petroleum now known in the United States. Dur- 

 ing the same time, within the same territory and from the same 

 logical horizon, several separate gas fields of extraordinary 

 vigor and volume have also been brought to light. Following 

 these surprising developments in Ohio, similar discoveries of 

 have been made in the contiguous districts of northeastern 

 and central Indiana The new gas field of this last-named 

 State, is by far the largest continuous gas field known in the 

 world, its original area being not less than 2000 square miles. 



The stratum which has yielded these remarkable supplies is 

 the Trenton Limestone, one of the best known elements in the 

 geological scale of North America. Although some phases of 

 its outcrops had long been recognized as petroliferous, no one 

 was prepared for its present enormous production. From single 

 wells, of inches in diameter, 5000 barrels of oil have flowed 

 in a day. and to at least one well a total production of 200,000 

 bbls. is already credited. The gas wells of the formation are 

 equally prolific. The maximum production thus far has been 

 recently reached in an outflow of 33,000,000 cubic feet a day 

 from a single well. A score of wells can be named, each of 

 which exceeds in its daily flow 10,000,000 cubic feet of gas. 



It is well known that the oil market of the country is in no 

 sense an open market in which prices can freely adjust them- 

 selves to values. The severest possible repression has been 

 imposed upon the production of the Trenton limestone, by 

 fixing and holding the price of the oil derived from it at 15 

 cents a barrel, but the inherent vitality of the new source is 

 shown in the fact that even at this rate more than 10,000,000 

 barrels were brought to the surface in 1880. Natural gas 

 derived from the same formation is now furnishing all of the 

 fuel and much of the artificial light that is used by a popula- 

 tion of at least 500,000 people within the districts named 



