EFFECT OF IGNEOUS INTRUSIONS ON OIL 669 
throughout, or at least be of such an organic nature as to account 
for their furnishing the great quantities of oil in these fields. The 
shales which are exposed over nearly the whole area, however, 
CCS ee ed a 
Fic. 1.—Hypothetical section showing basalt intrusion reaching the surface 
and resultant conditions in the intruded beds, conducive to the accumulation of oil. 
The two deep wells tapped the oil zone after penetrating the basalt, while the well 
nearest to the’cone was abandoned in the basalt. 
show signs of oil only near intrusions, and in all the exposures 
examined were of a uniform inorganic nature. 
The migration of oil in impervious shales of this nature takes 
