INTRODUCTION 
During the past year petroleum geophysics in the United States has 
entered a new, highly important phase of its gradual development and 
increasingly satisfactory application to the mapping of subsurface geo- 
logical structure. With the advent of seismic reflection shooting, the 
locale of most intense geophysical prospecting has shifted from the Texas 
and Louisiana salt-dome areas to the Mid-Continent states of Oklahoma 
and Kansas. With this change has come a wider appreciation by geolo- 
gists and executives of the utility of geophysics. In addition, more 
geologists now realize that geophysics is not a separate field, but a means 
of amplifying their ability to determine geological conditions. In short, 
we have passed from the more or less mysterious isogam and gamma 
stage to the foot stage in geophysical interpretation. 
To date it has been difficult to induce most geophysicists to 
participate in the presentation or discussion of papers. This attitude is a 
result of the youthfulness of the science. A change may be expected 
with age. The present period in the science of petroleum geophysics is a 
recapitulation of the history of geological science in the oil industry prior 
to the formation of The American Association of Petroleum Geologists. 
It is to be hoped that the geologists, with their experience in the value of 
codperation, will imbue geophysicists with their ideas. 
To forward this spirit of codperation and to acquaint more geologists 
with geophysical methods, The American Association of Petroleum Geol- 
ogists, through the Society of Petroleum Geophysicists, solicited geo- 
physical papers to be presented at the San Antonio meeting and later 
to Le published in the Bulletin. The following papers, which were pre- 
sented at San Antonio, represent a fair cross section of the present de- 
velopment of petroleum geophysics. Some of them present new, unor- 
thodox ideas and, though subject to discussion, should stimulate new 
thought. Such discussion is very necessary, is cordially invited, and if 
given will accomplish one of the objects in the presentation of these 
papers. 
To the various authors and their respective companies, we are greatly 
indebted for the release of material and the preparation of the papers. 
G. H. WEsTBY, chairman 
San Antonio Program Sub-Committee on Geophysics 
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