132 E. E. ROSAIRE AND JOSEPH L. ADLER 
of the misclosure in the three traverses through which it is believed to 
pass. These are from west to east, plus rro feet, plus 80 feet, minus 
330 feet, suggesting a fault having its maximum displacement near 
the common side of the eastern and middle traverses and its upthrown 
side on the north. 
Paleontological data and lithological logs from two wells, one on 
each side of the supposed fault, appear to indicate a maximum throw 
of about 1,200 feet. As the paleontological markers used have not been 
thoroughly tested in the region, however, this amount of throw may 
be erroneous. The horizon used was a calcareous bed characterized by 
the simultaneous first appearance of Textularia mayort and Nonion 
scapha in one well, and in the other well the simultaneous first appear- 
ance of the same two species in shale a little more than 30 feet below 
it. No species whatever of Textularia or Nonion were found above this 
horizon in either well. Correlated on the basis of the calcareous bed 
referred to, a good correspondence between the principal calcareous 
and sandy horizons in the lithologic logs of the two wells was found. 
The two faults noted by the writers in the course of the research 
were rendered conspicuous by the large misclosures they produced on 
some of the traverses they crossed. Faults with less differential of dis- 
placement would easily pass unnoticed because of the small misclosure 
they produce. In conclusion, therefore, it may be said that faults hav- 
ing small differential of displacement will go undetected in dip-reflec- 
tion work and may constitute one of its greatest sources of error. 
654 
