60 
MAURICE G. MEHL 
The destruction of organic matter by denitrifying bacteria is 
not confined to the nitrogenous portions alone, however; in time 
the fats are also attacked and, in the normal process of decay, 
these too are entirely destroyed. Obviously, other factors being 
equal, in those regions in which denitrifying bacteria are most 
active the destruction of the fatty portions of organisms should 
be fastest and most complete; there should be the least likeli- 
hood of the formation of petroleum. For ideal conditions in the 
formation of petroleum the denitrifying bacteria should be suf- 
ficiently active to denitrify the organic base, but their abundance 
should not make possible the excessive destruction of the fatty 
portions. 
Vaughan has pointed out the part played by denitrifying bac- 
teria in the precipitation of calcium carbonate from sea water 
and has stated that this activity, if not confined to tropical 
waters, is at least most marked in the warmer portions of the 
sea.^ Drew, in speaking of Bacterium calcis and other deni- 
trifying bacteria, says:^ 
Such action would be almost limited to comparatively shallow 
seas whose temperature approximated to that of tropical seas at the 
present time. 
Now, while such investigations offer no conclusive evidence 
as to whether denitrifying bacteria are sufficiently active to 
effectively destroy the fatty portions of decaying organic matter 
in the equatorial belt, they do indicate that the destruction would 
be progressively greater toward the equator, other factors being 
equal. From this standpoint it does not seem unlikely that 
throughout past times there have been fluctuating boundaries 
beyond which, toward the equator, conditions for the formation 
of petroleum have been subnormal. 
^ Vaughan, T. W., Preliminary remarks on the Bahamas, with special reference 
to the origin of the Bahaman and Floridian oolite : Carnegie Inst. Washington, 
Pub. no. 182, pp. 47-54, 1914. 
2 Drew, G. H., On the precipitation of calcium carbonate in the sea by marine 
bacteria, and on the action of denitrifying bacteria in tropical and temperate 
seas: Carnegie Inst. Washington, Pub. no. 182, pp. 7-45, 1914. 
