Exploratory drilling in the Four Corners-Intermountain area increased slightly in 1979 with 170 wells drilled. Forty-four of the wells were successfully completed for a success rate of 26%, up from 17.1% successes in 1978. Although drilling activity was down in Arizona, Nevada, and southwest Colorado, there were sharp increases in western New Mexico and Utah. Total exploratory footage drilled was down 11% in 1979, with 840,260 ft drilled in all exploratory categories. Development drilling decreased 5% from 1978, with 955 holes drilled, most of which were in the San Juan basin. The region's most significant discovery was again in the Overthrust belt of northern Utah, where Amoco's 1 Bountiful Livestock produced oil and gas from the Jurassic Nugget Sandstone. Two other wild at tests in the area reported significant shows. The large Pineview field in the Overthrust belt produced 3.9 MMBO and 4.4 BCFG in 1979. Seven oil and gas discoveries were made in the Uinta basin, and 2 significant oil discoveries were reported from the southern Paradox basin. Nevada's third oil field went on production in 1979 from Tertiary volcanic rocks. Six "offshore" wildcat wells drilled in Utah's Great Salt Lake by Amoco in 1979 have been temporarily abandoned. At least 2 of the wells had significant oil shows in Tertiary basalt. Exploratory and development drilling trends indicate that activity will remain high in the area for 1980.