APPLICATION OF REFLECTION SEISMOGRAPH! 
EUGENE McDERMOTT? 
Dallas, Texas 
ABSTRACT 
This paper describes in detail a reflection seismograph survey of western Henderson 
and eastern Navarro counties, and covers the area just north of the Mexia-Powell oil 
field. A number of faults are located and closure is indicated on two. A cross section of 
the area shows the relation of the reflection records to the subsurface structure. Re- 
flections were obtained throughout the area on the Pecan Gap and a basal member of 
the Austin chalk. Contour maps on these two reflection horizons are included. 
INTRODUCTION 
The area surveyed in this application of the reflection seismograph 
lies just north of the Mexia-Powell fault-line fields in eastern Navarro 
and western Henderson counties, Texas, and has long been considered 
a favorable area in which -to explore for a possible extension of this 
line of fields. At least twenty dry holes have been drilled in this area. 
A seismograph survey such as the one under consideration would have 
made possible the selection of the best location, structurally, so that 
one, or at most two, wells would have thoroughly tested the area for 
the presence of oil. 
A total of approximately seventy-five depth determinations were 
made in a period of about two weeks, resulting in a cost per acre of 
somewhat less than ro cents. 
The author has attempted to present the data in the form of two 
contour maps, one of the top of the Pecan Gap chalk and the other 
of the basal member of the Austin chalk, a cross section with corre- 
sponding reflection records from which the depths to these two re- 
flecting horizons were made, an enlarged view of a typical record 
showing the relation between the reflection events and the section, 
and has endeavored to make these as nearly self-explanatory as pos- 
sible. 
! Presented before the Association at the Oklahoma City meeting, March 25, 1932. 
Manuscript received, June 4, 1932. 
2 Geophysical Service, Inc., 1311 Republic Bank Building. 
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