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PLATE VI 
Mesotrypa dubia n. sp. 
1. Tangential section x 20, 
2. Longitudinal section x 20. 
Pierce limestone. Murfreesboro, Tenn. ¥ 
Dekayella ridleyana n. sp. 
3. Longitudinal section x 18. 
4. Tangential section x 18. 
Ridley limestone. Salem, Tenn. 
Heterotrypa patera n. sp. 
5. Longitudinal section x 18. 
6. Tangential section x 18. : 
Pierce limestone. Stokes Gannon Ford, 2 miles northwest of Mur- 
freesboro, Tenn, 
