ABSTRACT

The Girard coal field is in Richland County, Mont., and is surrounded by the Culbertson, Sidney, and Richey-Lambert coal fields.

In the north half of the Girard field, four coal beds, the D, F, G, and H, have been mapped along the badlands south of the Missouri River. The G and H beds, exposed in the Cedar Coulee quadrangle south of the Missouri River, are correlative with the E and F beds of the Culbertson field in Roosevelt County north of the river Subsurface data support this correlation and provide data on the areal extent of these beds.

The correlation of the beds between the north and south parts of the Girard field is complex. In the south half, names derived from local mines were applied to many of the beds, and their relative stratigraphic positions are less certain due to the poor exposures of the beds. For example, the H bed of the north half is correlative with the beds mapped as the Prittegurl and Gardner beds in the south half of the Girard field.

Correlations between the southern Girard field and the adjacent Sidney and Richey-Lambert fields are tentative. Additional subsurface data are required.

The Pust bed is the major coal bed in the Richey-Lambert field, attaining a thickness of 40 ft. (12.2 m) south of Burns Creek. In the vicinity of Lambert, Montana, the bed is split. The upper split may be correlative with the Prittegurl bed of the Girard field.