Abstract

Surface correlations based largely on paleontologic criteria are being carried into subsurface work, often resulting in erroneous correlations. Type surface sections depend on many unconformities and sharp faunal changes for their delineation. In the basins, there are few if any unconformities and there are few readily identifiable faunal changes to denote the contacts between formations and groups. Consequently there will be a mixing of faunas such that it is difficult to designate by paleontology a definite contact between two formations.

Paleontology, paleobiology and lithology must be augmented by electric log analysis and study of sedimentation as bases for subsurface correlation.

All techniques should be used for sub-surface correlation. Paleontology should, however, be used as a tool to supplement sub-surface geologic correlations, rather than making geologic correlations fit into paleontologic correlations.