Order Pterioida Newell 1965
Family Myalinidae Frech 1891
Genus Septimyalina Newell 1942
The bivalve Septimyalina perattenuata has been a rare recovery so far. This single specimen is the only example from both localities. I can observe a columnar prismatic layer on this shell, which is hard to photograph using light.

References
- Newell, N. D., 1942. Late Paleozoic pelecypods: Mytilacea. State Geological Survey of Kansas, Bulletin. 10(2): 1-115. p.p. 64–65