Ch. 31] REFERENCES 577 



sandstone + clastic limestone 



1. Ratio of 



shale 



sandstone 

 2. Ratio of 



shale -f- limestone 



3. Number of quartz-sandstone beds. 



4. Average thickness of quartz-sandstone beds. 



5. Composite thickness of quartz-sandstone beds. 



6. Average thickness of all beds. 



For the petroleum geologist the object of constructing all such maps 

 is to ascertain any apparent relationships between the trends and 

 numerical values of isolithic lines and the incidence of oil and gas. 

 Undoubtedly numerous additional types of maps can be drawn for the 

 purpose of showing various properties of sediments, but all the types in- 

 dicated above can be constructed from data available from any of 

 the several types of well log and core information usually available to 

 the student of subsurface geology. 



REFERENCES 



Archie, G. E. (1942). Electrical resistivity log as an aid in determining some 

 reservoir characteristics: Amer. Inst. Min. Metall. Engrs., Petroleum Technol- 

 °9V> PP- 54-62. 



Atwill, E. R. (1942). Progress of stratigraphic studies in California: Bull. Amer. 

 Assoc. Petroleum Geol., vol. 26, No. 2, pp. 153-161. 



Beers, L. C. (1941). Radioactivity logging through casing: Petroleum World, 

 Nov. 1941. 



Bell, K. G., Goodman, C, and Whitehead, W. L. (1940). Radioactivity of sedi- 

 mentary rocks and associated petroleum: Bull. Amer. Assoc. Petroleum Geol., 

 vol. 24, No. 9, pp. 1529-1547, Sept. 1940. 



Carll, J. F. (1875). Report of progress in the Venango oil district: Second Geo- 

 logical Survey of Pennsylvania. 



Dickey, P. A. (1944). Natural potentials in sedimentary rocks: Amer. Inst. Min. 

 Metall. Engrs., Petroleum Technology, pp. 39-48. 



, Sherrill, R. E., and Matteson, L. S. (1943). Oil and gas geology of the 



Oil City quadrangle: Topographic and Geologic Survey of Pennsylvania, 4th 

 ser., Bull. M-25. 



Guyod, H. (1944). Electrical well logging: A series of 16 articles published in 

 Oil Weekly, issues of Aug. 7, 1944, to Dec. 4, 1944, inclusive. 



Hills, J. M. (1949). Sampling and examination of well cuttings: Bull. Amer. 

 Assoc. Petroleum Geol, vol. 33, No. 1, pp. 73-91, Jan. 1949. 



Krumbein, W. C. (1932). A history of the principles and methods of mechanical 

 analysis: Jour. Sed. Petrology, vol. 2, pp. 89-124. 



(1945). Recent sedimentation and the search for petroleum: Bull. Amer. 



Assoc. Petroleum Geol., vol. 29, pp. 1233-61. 



