The rate of exploratory drilling in North and South Dakota continued at a slightly increased rate, and over-all results were about equal to 1960. This increased drilling rate was in spite of the fact there appears to have been an over-all industry retrenchment in exploration. A comparison of exploratory drilling, 1960-1961, is shown in Table I. The number of successful new-field wildcats declined from 6 to 3, but the combined total successful new-field wildcats, outposts and deeper-pool wildcats totaled 18, compared with 17 in 1960. South Dakota did not enjoy an exploratory success. Table II shows the production comparison with 1960, and Table III compares the level of seismic activity. Figure 1 shows the location of major fields, new discoveries, new deeper-pay discoveri s, pool extensions, and significant wildcat failures.

For the second successive year exploratory drilling in Montana showed a marked increase. A total of 184 tests were drilled in 1961, only 11 less than the record high of 195 in 1956. Percentagewise the 1961 activity level was up 14% over 1960 and 60% above 1959. The 1961 success ratio was slightly under 4%. New-field wildcat successes were near normal. Unsuccessful outpost drilling accounted for the poor statistical showing.