FUTURK OF THE FIELD 649 



In Tennessee the same warped eastward-dipping homocline prevails, 

 with a marked outlying fold a few miles from the eastern border. Es- 

 sentially similar structure exists in Alabama. 



Notwithstanding the overthrust faults along the boundary between the 

 Appalachian folds and the basin from the Kentucky line southward, the 

 structure is distinctly favorable to the occurrence of oil at many points. 

 In itself this would favor the future development of profitable pools in 

 the region south of West Virginia; but, unfortunately, as noted else- 

 where, other factors entering into the problem seem to make such devel- 

 opment unlikely. 



EVIDENCE OF CHARACTER OF RESERVOIRS 



In Pennsylvania and most of AYest Virginia there are porous sands 

 affording ideal reservoirs for oil, with cap-rocks for confining the same, 

 at a large number of horizons in both the Carboniferous and Devonian 

 strata. Going south, liowever, there is a distinct deterioration in the 

 character of the reservoirs. In Tennessee it is found that the sands are 

 very close and tight and the limestones commonly without the porosity, 

 due to dolomitization, necessary to make them available as reservoirs. ^^ 

 Most of the oil found has been reported from crevices resulting from solu- 

 tion or weathering in the portions of the limestones near the surface. ^ 



EVIDENCE OF DEGREE OF DYNAMO-CHEMICAL ALTERATION 



The principle recently advanced by David White,^^ that there is a defi- 

 nite and fixed relation between the distribution of oils and the fixed car- 

 bon of pure coals, opens a new field of thought. If the postulated relation 

 can be established, as no^v seems likely in spite of the numerous variations 

 and exceptions, it is likely to be the most important discovery pertaining 

 to oil since the development of the anticlinal principle. It affords a meas- 

 ure of dynamo-chemical change or metamorphism, of the amount of which 

 there has hitherto been no clue, and explains many puzzling features in 

 the occurrence and distribution of oil and gas. It is of the greatest value 

 in determining prospects in new territory. 



Applying the principle to the xippalachian field, it is found that the 

 occurrence of 65 per cent to 70 per cent of fixed carbon in pure coals es- 

 tablishes a sort of rload line as regards commercial deposits of oil or gas. 

 "Where coals range from 60 to 65 per cent, fixer! carbon gas may be found 

 in quantity, but little commercial oil. Where coals range from 55 to 60 

 per cent, fixed carbon oils are found iu abundance, with abun riant gas. 



22 M. .T. Mnnu : Tonn. Geol. Survey, Bull. 2-E, pp. 37-38. 



23 "Some Relations in Origin between Coal and Petroleum." .Tour. Wash. Acad. Sci. 

 vol. .5, no. 6, March 19, 1915, pp. 189-212. 



