Introduction 9 



geologic mapping is a necessity. Subsurface phenomena would be diffi- 

 cult to interpret adequately without exposed stratigraphic and structural 

 relationships having first been observed and studied. The student of 

 subsurface geology should spend at least three years in stratigraphic 

 and paleontologic laboratories in order to become familiar with funda- 

 mental techniques applied in subsurface problems. This period of training 

 should be divided among the Pacific Coast, the Gulf Coast, and the Mid- 

 continent areas. One year should be devoted to geophysical work, another 

 to logging methods, and the last to petroleum and production engineering. 



Future of Subsurface Geology 



Most of the oil fields and ore deposits in the future will be discovered 

 from the application and coordination of subsurface investigations. 



The number and complexity of subsurface methods now employed 

 require specialists. There are those who devote their efforts to lithologic 

 studies, to paleontologic investigations, and to logging methods, and 

 others to interpretation of structural conditions. The field of geophysics 

 offers an unlimited opportunity for the subsurface geologist whose responsi- 

 bilities are to synchronize electrical and gravity data with stratigraphy and 

 structure. It is essential that each specialist know the position and rela- 

 tionship of his field to the general subsurface problem involved. 



Subsurface geologic methods and approaches as employed by the 

 petroleum industry have not yet been fully accepted or utilized by the 

 mining industry in exploration and exploitation. In the early history of 

 mining only the surface or near-surface deposits were exploited and de- 

 veloped. Today it is required that possibilities of deeper ore concentra- 

 tions be considered. Cram'* comments: "Mineral geologists must be 

 permitted by the mineral industry to spread their wings on a full-time 

 basis, not on a consulting basis, if the nation's undiscovered reserve of 

 minerals is to be developed." 



Subsurface investigations are scheduled to occupy an important posi- 

 tion in engineering geology. Before a civil engineer can properly design 

 any structure, he should be versed in the materials upon which his struc- 

 ture is to rest or in which his work is to be carried out. In any engineering 

 project, preliminary investigations are required and should be undertaken 

 with two objectives in view: (1) the evaluation of subsurface conditions 

 at and in the immediate vicinity of the proposed site that may affect the 

 work program, these conditions generally involving local geologic struc- 

 ture and distribution and character of undergound water; and (2) the 

 determination of the character of rock types expected during the progress 

 of construction. 



Many projects involving tunnels, excavation, earth movements, 

 bridge, dam, and building foundations, and water supply require the 



^ Cram, I. R., Geology Is Useful: Am. Assoc. Petroleum Geologists Bull., vol. 32 no. 1, pp. 7-8, 

 Jan. 1948. 



