The total drilling in eastern and northwestern Colorado and western Nebraska declined from 998 wells in 1964 to 979 wells in 1965. This decrease of 1.9% is not as dramatic a decline as has been experienced during the past few years. Exploration drilling declined by 34 wells in Colorado and by 4 wells in western Nebraska during 1965, but development drilling increased from 1964. The Denver basin of Colorado and Nebraska was the site of 81% of all exploratory drilling in the report area, and the producing areas again were extended northward by discovery wells drilled during 1965. It is believed that activity during 1966 in the Denver basin, southeastern Colorado, and the Nebraska Panhandle will continue at about the same level as during 1965. Increased exploratory work is a ticipated in northwestern Colorado because of the completion of natural gas pipelines and the Phillips Petroleum Company No. 1 Fork "A" discovery in northeastern Utah.

Geophysical activity probably will increase in the Sand Wash basin of northwestern Colorado. This increased seismic and gravity work will be concentrated in the western part of the Sand Wash basin along the northeastern flank of the Uinta uplift.