16 IOWA ACADEMY OF SCIENCES. 



burst beyond all reasonable bound at the slightest provocation There is scarcely a 

 county in the State where the problem has not been agitated to a greater or less 

 extent. Some have even gone to considerable expense in testing but without 

 success. 



The excitement occasioned by the discoveries of gas and oil in Pennsylvania, 

 Ohio and Indiana was second only to that of gold in California. The rapidity with 

 which the new fuel was utilized everywhere is fresh in the minds of many. The 

 complete revolutions wrought in the various industries are familiar to all. 



With gas and oil in abundance m the neighboring states; with a close similar- 

 ity of geological formations; with an expectant people already testing in different 

 parts of the State, the question naturally arises: What are the probabilities of 

 obtaining these substances in Iowa? 



Before attempting an answer, however, it may be desirable to review briefly the 

 conditions of a successful flow. These conditions fall under two heads: 



(1) The Origin. 



(2) The Accumulation. 



Origin. — The different theories concerning the origin of natural gas and mineral 

 oil need not be considered in detail here. Nearly all geologists now believe that 

 organic matter buried in the rocks at the time they were laid down is the real 

 source of petroleum; some regarding it as a kind of distillation through means of 

 moderate heat; some, as the result of decomposition. 



Manner of Accumulation.— Conimxy to popular opinion petroleum is a widely 

 distributed substance. The well known dolomites of Chicago contain large quan- 

 tities. Orton has shown that the Waterliuie formation, of Ohio, which is a com- 

 pact uiagnesian limestone having a thickness of 500 feet in places, contains not less 

 than 2,500,000 barrels of oil to the square mile. This is rock through which the 

 oil is disseminated so as to be perfectly unavailable; yet, if it could be gathered 

 into one place that contained in only three townships would equal nearly 260,000.000 

 barrels, or the total amount obtained from the Pennsjlvania and New York oil 

 field up to the year 1885. Now, in Iowa there are doubtless rocks as rich in oil as 

 the Ohio Waterlime. The Lower Carboniferous limestones in the southern part of 

 this State are good examples. 



With oil almost universally distributed, what are the conditions of its accumula- 

 tion in quantities of commercial value? P'or the financial success of an enterprise 

 of this kind four conditions must be fulfilled. The absence of any one of them can 

 only result in failure. There must be: 



(1) A suitable receptacle or reservoir to allow the oil and gas to accumulate. 



(2) A non-porous cover to retain these substances. 



(a) A particular geological structure or arrangement of strata. 



(4) A pres-sure suffiuent to force the oil and gas to the surface. 



The Resercoir is commonly a coarse sandstone, conglomerate or porous lime- 

 stone. There rocks allow the ready transmission of liquids or gases from one part 

 of a stratum to another. 



In order that the gas or oil may be retained within the porous stratum, some 

 close grained rock must overlie it. This impermeable layer is usually found in 

 some shale. 



Thus far the origin and conditions of accumulation of the oil and gas are to be 

 found almost everywhere on the globe to a greater or less extent— wherever the 

 stratified rocks are laid down. With all these conditions fully satisfied there is 

 another very important factor — geological structure. The rocks must be tilted. 



