Nilwood Anticline

Location

T10 and 11N, R6W, Macoupin County (G-4)

References

Easton 1942, Ball 1952

Description

Easton (1942) and Ball (1952) both mapped the Nilwood Anticline as a southeast-plunging nose that trends southeast at the northern end and nearly south at the southern end. The Herrin Coal Member (Pennsylvanian) was the contouring horizon. Remapping of the Herrin Coal structure using additional control points shows an anticline that trends southsoutheast from Section 20, T11N, R6W, to Section 9, T10N, R6W, and has closure of about 20 feet (6 m) (Nelson 1987b). This feature corresponds closely with the southern part of the Nilwood Anticline as originally defined. Toward the northwest where Easton and Ball indicated slight nosing, Nelson's map shows a southeast-facing homocline.