o some natural gas.

In the United States nearly 40 per cent of the total production of
natural gas comes from West Virginia, about 17 per cent from
Pennsylvania, about 17 per cent from Oklahoma, and less than 10 per cent
from each of Ohio, California, Louisiana, Kansas, Texas, and several
other states.

One of the recent interesting developments in this industry is the
recovery of gasoline from the natural gas. This is obtained by
compression and condensation of the casing-head gas from oil wells, and
also, more recently, by an absorption process which is applied not only
to "wet" gas from oil wells but also to so-called "dry" gas occurring
independently of oil. It is a high-grade product which in recent years
has amounted to about 10 per cent of the total output of gasoline for
the United States.

GEOLOGIC FEATURES

Natural gas, like oil, originates in the distillation of organic
substances in sediments, and migrates to reservoirs capped by impervious
strata. It is commonly, though not always, associated with oil and coal.
The geologic features of its occurrence have so much in common with oil
that a description would essentially duplicate the above account of the
geologic features of oil.

ASPHALT AND BITUMEN

ECONOMIC FEATURES

Asphalt and bitumen are not used as energy resources, but they have so
much in common with oil in occurrence and origin that they are included
in this chapter.

Asphalt and bitumen find their main use in paving. Other important uses
are in paints and varnishes, in the manufacture of prepared roofing, for
various insulating purposes, and in substitutes for rubber.

Nearly the entire world's supply of natural asphalt comes from the
British Island of Trinidad and from Venezuela. Both of these deposits
are under United States commercial control probably affiliated with
Dutch-English interests. Prior to the war about half the product went to
Europe and half to the United States. Large amounts of asphaltic and
bituminous rock, used mainly in paving, are normally produced in Alsace,
France, and in Italy. Prior to the war both the Alsatian and Italian
deposits were under German commercial control. Their output is
practically all consumed in Europe.

The United States takes a large part in the world's trade in natural
asphalt, by importation from Trinidad and Venezuela, and by some
reexportation chiefly to Canada and Mexico. The United States also
produces some natural asphalt and