- DEPTHS FROM SEISMIC TIME-TRAVEL CURVES 131 
this paper, the method described here was found to check admirably 
with later determined well logs, and it is doubtful if the difference in 
the velocity of the shock waves across and along the beds in these 
cases was very pronounced, or that they introduced a serious error in 
the results. 
In support of the method just described, it may be said that it 
facilitates mathematical work to a high degree, enables the computer 
to break up the problem into sections which aid him in placing the 
observed time differences of the records in their proper places in the 
subsurface chart, and checks to a close margin calculations made 
from much more lengthy derivations. 
I wish to express my appreciation to Mr. J. E. LaRue of the 
Humble Oil and Refining Company for permission to publish this 
article. 
791 
