272 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1950 



11. Pratt, Wallace E., Distribution of petroleum in the earth's crust. Bull. Amer. 



Assoc. Petrol. Geol., vol. 28, pp. 1506-1509, 1944. 



12. Pratt, Wallace E., Petroleum on continental shelves. Bull. Amer. Assoc. 



Petrol. Geol., vol. 31, p. 657-672, 1947. 



13. Jones, B. E., Developed and potential water power of the world. U. S. Geol. 



Surv. mimeographed Information Clrc, 1948. 



