ANNUAL MEETING 81 
wells. The economic importance of faults and their influence on oil and gas accumula- 
tions are being stressed. 
The type of faulting on Gulf Coast salt domes is discussed and in addition some 
ideas are given in regard to salt-dome tectonics in general. 
It is pointed out that stratigraphic irregularities, hitherto explained by lensing, 
should be reconsidered from a tectonic point of view. Tectonics in the evolution of our 
geologic knowledge of Gulf Coast salt domes has not received its share of attention. 
4. M. Ewing, A. P. Crary, and J. W. Peoples, Seismic Tests on Anthracite.(By Title) 
Refraction profiles 400 feet long were run over anthracite outcrops and over shales 
between veins. A profile directly on the anthracite showed a velocity of 5,000 feet per . 
second. The velocities so obtained were too nearly equal for prospecting. 
. C. A. Heiland, Confirmation of Reflection Wo rk in Canada by Drilling. 
The paper brings out the fact that although the reflection geophysicist may be in- 
clined to consider his work a matter of routine physical measurements, he must be able 
to recognize geologic situations that are apt to interfere with correct inane: and to 
adapt his field and interpretative technique to same. 
The area covered by the survey is situated near Duvernay, on the Seiden 
River, in Alberta. A number of shallow and two deep wells had been drilled there, and 
a magnetic survey been made. The stratigraphic and structural conditions deduced 
from the preliminary work are discussed in detail. 
The problems confronting the reflection survey arose from the variations in di- 
mensions and petrographic character of the strata composing the glacial drift. They 
affected, (a) the near surface time delay, (b) the accuracy of average velocity deter- 
minations, and (c) the character of seismic impulses. How these difficulties were ana- 
lyzed and partially overcome is discussed in the sections on field procedure, inter- 
pretation, and results. 
A graphical method of logging and correlating impulses of adjacent stations was 
employed. Traverses and contour maps thus obtained indicated that the wells referred 
to had been drilled off structure. 
6. G.H. Westby, Effect of Surface and Near-Surface Beds in Reflection Seismic Results, 
7. J. Brian Eby and Robert P. Clark, Relation of Geophysics to Salt-Dome Structures. 
This paper presents eighteen geophysical maps covering nine salt domes and deep- 
seated structures of the Texas and Louisiana Gulf Coast. Two shallow domes, namely, 
Moss Bluff and Fannett, are given. Fannett is a gravity maximum, and Moss Bluff is 
a combination of a gravity minimum and maximum. The Sugarland dome is given as an 
example of a medium-depth structure, which is indicated by the torsion balance as a 
minimum. Six deep-seated structures are shown, including Sheppards Mott, Pledger 
Mykawa, Tomball, Livingston, and English Bayou-Gillis. The deeper seated structures 
invariably show a gravity minimum influence. 
A refraction seismograph map of Moss Bluff is given, and reflection seismograph 
maps are given for Sheppards Mott, Tomball, and English Bayou-Gillis. A magnetic 
map of the Fannett field is likewise presented. 
8. Symposium of Geophysical Activity Throughout the United States and Som 
Foreign Countries. 
G. H. Westby, Henry Salvatori, Joseph L. Adler, H. B. Peacock, John H Wil 
son, E. G. Leonardon, O. C. Lester, Jr. 
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