The gas occurrences are associated with the Tertiary rocks which now occupy the ancient gulf of central Burma, other occurrences with similar rocks of the Assam basin of deposition, which extended to the Arakan coast of Burma. Both oil and gas appear to have been formed under brackish-water conditions, being found neither in fresh-water sediments nor in deep sea-water deposits. Gas seepages are very common in Burma; many are dissociated from oil. Little use has been made even of extensive gas fields--even where one well yielded 39 million cubic feet per day--excepting in strategic localities. Other gas seepages are connected with the famous mud volcanoes, especially of Minbu and the Arakan coast. Much attention has been paid to the gas associated with the oil fields. Sinc 1908 there have been stringent laws regulating the conservation of gas pressures in the fields and the long life of the Burmese oil fields is attributed by many primarily to these regulations.