52 G. H. WESTBY 
The correlation of reflections with known formations and cali- 
bration of the velocity was made by shooting across the well in 
the SE. NW. SE. of Sec. 28. A partial graphic log of this well is 
shown in Fig. 5. The four most important records obtained in this 
original shooting are shown in Fig. 6. No. 1-SW. was shot across the 
described well. After study of the possible velocities in the area, it was 
determined that the reflection whose trough is at .506 was from a 
member of the Dutcher limestone, and that the reflection whose 
trough is at .562 was from either the base of the Mississippi lime or 
the Viola limestone. In either case, structure would be satisfactorily 
portrayed, since the shortening over structure is usually at the top of 
the Mississippi lime and there is little change in the thickness of the 
Chattanooga shale. The reflection whose trough is at .607 was as- 
sumed to be from the Arbuckle limestone. 
The record 15—A-N, and its correlation with 1-SW. which appears 
quite clear, indicated with considerable definiteness the presence of 
the structure. The steep dip off to the south, as evidenced by corre- 
lation with record 15—A—S., which shows a drop of 50 feet in about 
1,100 feet, and the dip to the east shown by correlation with record 
14-SE. are typical of these small structures. Even without corrections, 
the arrival times of the reflections show the presence of structure. 
Since well control was available, both to the southeast and the 
southwest, indicating low areas (see Fig. 1), it was thought unneces- 
sary to do more work in these directions. From the control obtained 
one must contour this small structure with the north-south section 
line as an axis of symmetry. 
Since this structure appeared more or less typical and seemed to 
fit in very well with the subsurface data drawn by Gartner, it was 
thought to be adequate evidence on which to drill a well. Although 
there are twelve reflection points determined in about 320 acres, this 
control is now recognized to be what might be called a detailed re- 
connaissance for this area. 
It must be remembered also that this type of shooting is subject 
to all the errors incurred in reflection seismic work, which have been 
discussed by the writer,! and is much inferior to the more recent 
method of shooting this type of structure which has been developed. 
Nevertheless, the accuracy was deemed entirely satisfactory for this 
particular area. Accordingly, a test well, intended to go to the Wilcox 
1 FE. McDermott, Application of Seismography to Geological Problems, A.A.P.G 
Bull., 15 (1931) pp. 1311-1334. 
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