In this district in northeastern Texas development drilling activity was 20 percent below that of 1962; 992 wells drilled or 248 less than in 1962. Exploratory drilling totaled 260 wells, of which 15 percent were successful. There were 13 new fields discovered and 15 successful extensions in Cretaceous and Jurassic trends. Total geophysical activity increased from the previous year; but gravity work decreased and core-drill activity was less. The counties experiencing the largest lease plays were Houston, Angelina, and Wood.