Correlation of the several sandstone members of the Springer section has been done by use of the self-potential and resistance curves of the electric logs of the wells of the field. Examination of well cuttings has been useful in correlating the upper members of the Humphreys sandstone.

Delineation of these curves in thirteen west-east cross sections shows local uniformity in the several sandstones of the Springer which can be considered due to consistent sedimentation; and also local variations and disappearance of the beds due to interrupted or variable sedimentation or to folding and faulting. These last two possibilities must depend upon the interpretation of the data in accordance with the general principles of sedimentary and structural geology.

The northwest-southeast trending synclinal area between the major Milroy uplift to the southwest and the relatively minor Camp uplift to the northeast has on its southwest flank an involved series of serpentine folds in the supposedly incompetent Humphreys sandstone beds which are shown to be continuous unless there is clear evidence of faulting. This is done to simplify the picture and does not assume that minor faulting and folding are not present.

The usefulness of this paper depends upon the wealth of data which deep drilling on 10-acre spacing has made available.