S. W. Schoellhorn received a B. S. degree 

 in geological engineering from the Colorado 

 School of Mines in 1942 and did graduate 

 work in geophysics at the California Institute 

 of Technology. His 14 years of experience in 

 geology and geophysics includes field work, 

 interpretation, instrument operation, engi- 

 neering, research and development (particular- 

 ly in the seismic prospecting method) . In 1942 

 he was employed by the Seismograph Service 

 Corporation as a trainee observer, and since 

 that time, he has held the positions of observer, 

 party chief, party supervisor, and at present 

 is a senior research engineer in the Seismic 

 Research Department. He has supervised the 



design and development of well logging instruments, seismic instruments and 

 magnetic recorders. He is a member of the Society of Exploration Geophysicists 

 and the American Association of Petroleum Geologists. 



G. Frederick Shepherd graduated from 

 Hamilton College, Clinton, N. Y., in geology, 

 did post-graduate work at Northwestern Uni- 

 versity, 1930-1931, and at University of Chi- 

 cago, 1932-1935. He was geologist with Phil- 

 lips Petroleum Company, 1936-1940, and 

 geologist with Lane- Wells Co., Houston, 1940- 

 1941. Shepherd then was geologist with Wil- 

 liam Helis at New Orleans, 1941-1946, and 

 consulting geologist at New Orleans, 1946- 

 1948. From 1948-1953, he was chief geologist, 

 General American Oil Co. of Texas, Dallas; 

 again re-entering the consulting field in Dallas 

 from 1953-1954. He has been a partner in the 

 firm of Bettis and Shepherd, Dallas, since 

 1954. He is a member of the American Association of Petroleum Geologists, the 

 American Institute of Mining and Metallurgical Engineers, the American Associ- 

 ation for the Advancement of Science, and other geological societies. 



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