Devonian System

Type section: The Morgan Trail Member of the New Albany Shale was named by Lineback (1968, 1970) for a roadside park 1 mile (1.6 km) southwest of the type section in the NW¼ sec. 16, T. 3 N., R. 8 E., Scott County, Ind.

Description: At the type section the Morgan Trail consists of brownish-black to olive-black fissile siliceous shale containing pyritic calcareous laminae and beds. The thin hard pyritic beds are characteristic of this member, which is recognizable throughout the southern Indiana and northern Kentucky outcrop area but cannot be readily traced in the subsurface in southwestern Indiana. It lies above the Selmier Member and below the Camp Run Member of the New Albany Shale and ranges from 22 to 38 feet (6.7 to 11.6 m) in thickness in the shallow subsurface and in the outcrop area in southeastern Indiana (Hasenmueller, 1982). Fossils include linguloid brachiopods, Tasmanites, and silicified logs of the genus Callixylon.

Correlation: The Morgan Trail Member is considered to be stratigraphically equivalent to the lower part of the Grassy Creek Shale of Illinois, to part of the Antrim Shale of Michigan and northern Indiana, and to the lower part of the Gassaway Member of the Chattanooga Shale of Tennessee (Lineback, 1968, 1970).