The Paradox Basin is located in the four-corners area of Utah, Colorado, New Mexico, and Arizona. The U.S. Geological Survey has just completed a study assessing the potential for oil and gas discovery. They conclude that the area has potential for “560 million barrels of undiscovered oil, 12,701 billion cubic feet of undiscovered natural gas, and 490 million barrels of undiscovered natural gas liquids…” Read the report here (2.6 Mb).
There is also potential for oil and gas in the Holbrook Basin farther south in Arizona. This has yet not been assessed. The Holbrook Basin does, however, contain a large resource of potash (potassium ore) that is being developed. See: Arizona may become a major producer of potash.