CONTENTS. 
Part I.— General Features of the Region. 
Introduction. 
Chapter I. 1 heoretical discussion of the occurrence of petroleum and natural 
gas. 
General conditions in the Appalachian oil fields. 
Theory of accumulation of oil and gas. 
Origin. 
Movement in porous rocks. 
Places of accumulation. 
Application of theory in the Appalachian fields. 
Practical application of principles governing the accumulation of oil. 
Factors involved. 
Conditions necessary to determine subsurface structure... 
Position of sedimentary deposits when laid down. 
Summary. 
Chapter II.—Method of investigation. 
Field work. 
Construction of maps. 
Structural map of the key horizon. 
Convergence map. 
Map of oil sand. 
Chapter III.—General geology of the Steubenville quadrangle. 
Description of surface. 
Location./. 
Topographic features.. 
Geologic features showing at the surface. 
Section of rocks exposed. 
Key horizons. 
Measurement of intervals between key horizons. 
Contour map of Pittsburg coal and structure. 
Geologic features below the surface. 
Source of information. 
Convergence between beds. 
Convergence sheet. 
Discussion of conditions as shown by map of Berea sand. 
Possibility of the existence of other productive sands. 
Upper limit of saturation. 
Description of oil pools. 
Turkeyfoot pool. 
Knoxville pool. 
Island Creek pool. 
Bluck pool... 
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