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Fulda Bed

Lead Creek Limestone Member,

Pennsylvanian System


Type locality and use of name: A limestone that was supposedly exposed along the road between Fulda and New Boston in eastern Spencer County, Ind., was named the Fulda Limestone by Franklin and Wanless (1944, p. 88-89). Their stated type locality is in the S2SW¼ sec. 33, T. 4 S., R. 4 W. This locality has never been reverified, however, and a good exposure either near or in the actually intended type locality was described later by Thompson and Shaver (1964, p. 16) in the NE¼SW¼ sec. 11, T. 5 S., R. 4 W. They also assigned the Fulda member rank in the upper part of the Mansfield Formation. Still later, the Fulda was designated as the Fulda Bed, the lower part of the trip art Lead Creek Limestone Member (Shaver and Smith, 1974, p. 6).

Description: The Fulda Bed generally lies 10 to 15 feet (3.0 to 4.6 m) below the Ferdinand Bed and about 50 feet (15 m) below the top of the Mansfield Formation. It consists of limestone that is dark, dense, argillaceous, and hard. This limestone is 2.5 feet (0.8 m) thick in the type locality, but it ranges from a probable nondepositional 0 to about 2.5 feet (0.8 m). Shaly limestone and a few inches of shale split are present in some places. It is underlain by gray shale and also in some places by coal and siltstone it is overlain by gray shale and other elastic rocks. Both contacts are thought to be conformable.

Correlation: As a classificatory unit, the Fulda is flawed by the uncertainty surrounding its type exposure and therefore its type stratigraphic position. The present application of this term, however, extends to the limestone that Franklin and Wanless (1944) described as being 13 feet (4.0 m) below their Grandview Limestone (Ferdinand Bed here). This is also the application advocated by Hutchison (1959). Many exposures of the Fulda equivalent are known in Hancock County, Ky., adjacent to Spencer County, Ind., but there it is simply called the lower bench of the Lead Creek Limestone Member. The Fulda equivalent probably extends even farther south, however, to the lower of two limestones exposed near Morgantown in Butler County and described by Thompson, Shaver, and Riggs (1959). North of Spencer County, Ind., the Fulda has not been recognized with certainty, and single ledges of upper Mansfield limestones as far north as Warren County, Ind., should be simply called the Lead Creek Limestone Member (Shaver and Smith, 1974, p. 9).

In some places the Fulda contains an abundant microfauna representing the ostracod Zone of Amphissites rothi and the fusulinid Zone of ProfusulineIla, which have far-reaching meaning for correlating the Fulda and Lead Creek rocks in general with rocks of late Bashkirian age (global scale) and late Morrowan age (North American scale) in many parts of the world. (See the discussion on correlation in the Lead Creek article.)






 
 
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