A new vista of the petroleum potentialities of the Gulf Coast petroleum province of Texas and Louisiana has been opened by the developments of the past few years. The coastal salt-dome area has been extended eastward to, and across, Mississippi River. The area of good production has been extended southwestward to Refugio and may be expected to extend to the Rio Grande; it has been extended southward to Clay Creek, which lies in a hitherto practically non-productive zone, and seems probably to have been extended eastward to Terrebonne Parish, Louisiana. The maximum depth of production has been extended to 7,444 feet and the stratigraphic zone of good production has been extended down into the middle of the Claiborne. Deep and very deep salt domes have great potentialities, are being discovered in great numbers, but have certain drawbacks. The very deep salt ridges are unknown quantities. An enormously thick potentially productive stratigraphic section is present and offers great possibilities for production on such deep structures. A distinct tendency is shown for an increase of the Baume gravity and gasoline content of the oil with increasing depth and in part with increasing stratigraphic depth. That change foreshadows a progressive change in the mean character of the oil of the future and gives the only suggestion, as yet, of a possible downward limit to production. The general magnitude of the recoverable reserves of oil in the Gulf Coast area of Texas and Louisiana at a shrewd guess is: surely at least 3,500,000,000 barrels, probably at least 5,500,00 ,000 barrels, and possibly at least 10,000,000,000 barrels.