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NEW YORK STATE MUSEUM 



one mile, there is no sign of lnetamorpkisin, but on the contrary, 

 clear negative proof that the temperature of the series has never 

 been as high as 200° F. 



The gas of the Potsdam must have originated in or immedi- 

 ately below the stratum that contained it, but it could not have 

 originated as gas, contemporaneously with the sandstone forma- 

 tion. The Potsdam must have had an impervious cover before 

 the gas could have been developed. If the material had been in 

 the form of oil, the storage could well enough be accounted for. 

 The transformation of oil into gas is a process that we know to 

 be going on in nature and we can be sure that time enough has 

 elapsed in this instance to provide for its completion. That the 

 gas carries so much carbon loosely combined and ready to be de- 

 posited as free carbon or lampblack, matches well with this view 

 of its origin. 



Is there any possible source of petroleum revealed in this sec- 

 tion? The thin streak of Cambrian limestone, with its frag- 

 ments of the shells of Lingulella and Obolella and its hints of 

 trilobitic crusts shows the presence of life in the seas in which 

 it grew. Living matter, as we have seen, can be easily con- 

 verted, at least some forms of it, into the petroliferous series by 

 artificial processes. What man finds easy, nature, in her great 

 laboratory is likely to find still easier. It is not necessary to 

 hold that the limestone in its present state has yielded gas by 

 destructive distillation of its substance. Though darkened by 

 organic matter, there is but little in it that even under the pro- 

 cess named would be converted into gas, oil or tar. We may be 

 doubly sure that no limestone like the Cambrian which we find 

 here was the source of the gas or of the oil which preceded it. 

 In the first place, there is not organic matter enough, and in the 

 second, there has been no abnormal temperature. 



If, in the early stages of its formation, the organic matter, 

 the existence of which is attested by the fragments already re- 

 ferred to, had been converted into oil, either by a peculiar form 

 of decomposition according to Hunt, or by a process of dis- 

 tillation in which " time takes the place of temperature," accord- 

 ing to Peckham and others, the presence of petroleum or gas 

 would be satisfactorily accounted for. But it is to be borne in 

 mind that neither of the processes named has been proved to be 



