Margaret Elisabeth Stiles (18 December 1889 - 29 March 1965) was the daughter of a dentist, Dr. Edmund Pease Stiles and his wife Lucinda (Lucy) Copes Bell Stiles. She was born in Travis County, Texas.
At University of Texas at Austin
Little is known of Stiles' life prior to her time with SEG, with the exception of a references in the 1918 and the 1919 Bulletin of the University of Texas, at Austin, which lists her as "secretary" and as the "assistant to the director of the Bureau of Economic Geology and Technology," for the respective years. Ms. Stiles' brother, Edmund Bell Stiles is listed also as an "assistant in the Bureau of Economic Geology and Technology" in both the 1918 and 1919 bulletins.  A zoning review sheet from the city government of Austin, Texas refers to a house on 4200 Duval St. owned jointly by Margaret Elisabeth and her brother Edmund Bell Stiles, from 1918 to 1921, though it incorrectly lists them as aunt and nephew.
With E. E. Rosaire at the Independent Exploration Company
M. E. Stiles was co-author, with E. E. Rosaire, on several papers:
- Rosaire, E.E. and M. E. Stiles (1932) Distribution of salt domes in depth, Pan-American Geologist, vol. 57, no.4, p.316. May 1932. 
- Rosiare, E.E, and M. E. Stiles (1932), THE EFFECT OF GEOPHYSICS ON THE DEVELOPMENT HAZARD IN GULF COAST OIL FIELDS, Economic Geology, Lancaster, Pa., vol. 27, No..6, 1932, pp. 523-532.
- Rosaire, E.E. and M. E. Stiles (1936). ”EXPLORATION ON THE GULF COAST, TO 1936.” GEOPHYSICS, 1(1), 141-148. 
Clearly, Rosaire considered Ms. Stiles to be a colleague, and not a mere secretary or assistant.
Both Stiles and Rosaire are listed in the GEOPHYSICS paper as being affiliated with the Independent Exploration Company, Houston, Texas, a company founded by Rosaire in 1932. 
“She [Stiles] was an outstanding geophysicist, one of the very best of the time. She did everything, including managing crews in the field. In fact, the first time that I met her was in the field. She was digging shot holes. She was an original partner in Independent Exploration, at one time the second largest contractor, and it was always my feeling that she was one of the real brains of that outfit.”
Society of Exploration Geophysicists
M. Elisabeth Stiles was a charter member of the SEG. She served SEG in many capacities:
- one of the first two associate editors of Geophysics
- elected to the executive committee
- SEG Secretary-treasurer, elected 1937-1938 term
- business manager of SEG until 1939
- interim business manager, mid 1940s
Indeed, one story related by former SEG President, Sally Zinke, is that Ms. Stiles "saved SEG" during WWII, as the majority of geophysicists had been called to military service. Ms. Stiles continued to run SEG "out of her closet."
Stiles was the third person to receive SEG Life Membership in 1961 for her meritorious service to the SEG.
M. Elisabeth Stiles last address was listed as the Circle S Ranch, in Hamilton County, Texas. Her occupation at the time of her death is listed as "rancher".
Who was Elisabeth Stiles? (From The 1930s, the first decade, 75th Anniversary Issue) 
by Dean Clark
M. Elisabeth Stiles, the only woman on any of the founders lists, arguably set the standard for the volunteer efforts by members which have been the backbone of the society by assuming several very important assignments during much of the next two decades.She was one of the first two associate editors of GEOPHYSICS. She was elected SEG secretary-treasurer for the 1937-38 term, by which time the society had reached the stage (membership of 672) that a professional business manager was needed. However, plans to hire a business manager did not materialize and Stiles continued to handle most of SEG’s business affairs until J.F. Gallie took the job in 1939. (Kudos also to E.E. Rosaire, SEG president in 1934-35, who served during this time as unpaid advertising manager/salesman for GEOPHYSICS). Stiles also served as SEG’s interim business manager in the mid-1940s after Gallie resigned and a full-time business manager was being sought.
Unfortunately, other than her volunteer work with SEG during the society’s early years, virtually nothing is known about Stiles. Since she was among those asked by Barton to attend the first meeting to consider forming a professional society, it could be assumed that her professional credentials were well regarded by a very prominent figure in the field. This would seem supported by her early election to the executive committee, appointment to the original editorial staff of GEOPHYSICS, and subsequently being given responsibility, on two occasions, for most of the society’s business affairs.
But other facts about her are very limited. She was co-author of an article in the first issue of GEOPHYSICS and was listed as being employed by Independent Exploration Company, Houston, Texas. That, according to SEG’s Digital Cumulative Index, was her only publication in a geophysics-oriented journal. In SEG’s very early membership lists, she was listed as “Stiles, Elizabeth (Miss), 2011 Esperson Bldg., Houston, Tex” which, a cursory glance reveals, was the address of a very large fraction of SEG’s membership circa 1934. By the end of the decade, the spelling of her first name had been corrected and she was listed as “Stiles, Elisabeth, Circle S Ranch, Hamilton, Tex.” and that remained her address until she was listed in the “In Memoriam” section of the 1966 Yearbook. Apparently a Memorial was never published. If any one has additional information about Stiles’ life and career, please forward it to the SEG business office so that it can be added to the historical record. (Stiles received Life Membership, the third such honor in the history of the society, for meritorious service to SEG in 1961 but there is no record of an accompanying citation which would have provided the missing background information.)
The Charter Members of SEG
On 11 March 1930, the Society of Economic Geophysicists was founded by 30 geoscientists at the University Club in Houston. Donald C. Barton was elected president, E. E. Rosaire vice president, and John F. Weinzierl secretary treasurer. The Society's Constitution and Bylaws were adopted on 20 May by the following charter members:
D. C. Barton, L. W. Blau,E. E. Blondeau, D. P. Carlton, L. G. Christie, Henry C. Cortes, Helmut Dorsch, J. Brian Eby, D. G. Emrick, Eugene Fekete, Helmer Hedstrom, Christian Iden, A. I. Innes, Fritz Kaselitz, A. D. Kerns, J. E. LaRue, O. C. Lester Jr., W. H. Mannes, Eugen Merten, E. E. Rosaire, Russell F. Ryan, J. P. Schumacher, A. L. Smith, M. Elisabeth Stiles, A. D. Storm, Olaf F. Sundt, Raoul Vajk, John F. Weinzierl, L. H. Williams, and B. O. Winkler.
- University of Texas Bulletin, 1919.
- University of Texas Bulletin, 1918.
- Rosaire, E.E. and M. E. Stiles (1932) Distribution of salt domes in depth, Pan-American Geologist, vol. 57, no.4, p.316. May 1932.
- Rosaire, E.E. and M.E. Stiles (1932) THE EFFECT OF GEOPHYSICS ON THE DEVELOPMENT HAZARD IN GULF COAST OIL FIELDS, Economic Geology, Lancaster, Pa., vol. 27, No..6, 1932, pp. 523-532.
- Rosaire, E.E., and M.E. Stiles (1936) ”EXPLORATION ON THE GULF COAST, TO 1936.” GEOPHYSICS, 1(1), 141-148. doi: 10.1190/1.1437071
- Lawyer, Lee C., Charles Carpenter Bates, and Robert B. Rice (2001) Geophysics in the Affairs of Mankind: A Personalized History of Exploration Geophysics SEG Books, 2001.
- Dean Clark (1991). ”A founder and a Jack of all (geophysical) trades.” The Leading Edge, 10(12), 31-32.doi: 10.1190/1.1436799
- Clark, D., (2005) The 1930s, the first decade, 75th Anniversary Issue, THE LEADING EDGE