Drilling completions for 1963 were 13.7 percent less than previous year. About 25 percent of the activity was in and around the Niagaran reef play in St. Clair County, and 33 percent in south-central Michigan where there was an extensive development program in Hillsdale County on the southeast end of the Albion-Pulaski-Scipio Trenton-Black River fracture trend. The total footage drilled for the year was 1,851,996 feet, classified as 1,064,645 feet for development wells, 698,551 feet for exploratory wells, and 88,800 feet for service wells. The state produced less oil (15,971,747 bbls) but more gas (31,914,969 Mcf). The pay formations are summarized.