The Cat Creek oil field of central Montana is one of the oldest and most prolific oil fields in Montana. However, the physical characteristics of the crude, its method of entrapment, and stratigraphic position are anomalous.

The early use of excessive faulting to explain the field can not be substantiated by studies resulting from more recent exploration. Structural evidence seems to indicate a shifting of the subsurface axis toward the steep northern limb of the anticline.

The possible historical relationship of the Cat Creek field, the pre-Cambrian Belt rocks, and the Big Snowy anticlinorium is discussed.

It is concluded that the Cat Creek field has not been completely studied or evaluated and that such a study might lead to finding additional small, shallow oil pools and to a better exploration program for adequately testing the deeper Paleozoic section.

Structural conclusions made for the Cat Creek field may be extended to other structural features throughout central Montana, causing their re-evaluation for possible hydrocarbons.

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