Two more pelecypods from the Windom Shale for your viewing pleasure. Both are a little fragmentary due to the poor preservation and unstable matrix. They are notable for their size as I do not often find large specimens as intact as these.
Actinopteria decussata, note the faint decoration still visible, highly oblique shell body and extended wing.
Leiopteria conradi, Note the lack of decoration (just growth lines) and less oblique shell body.
Both specimens were collected in Buffalo Creek near Marilla, NY from the Windom Shale mbr. of the Moscow Formation (Devonian, Givetian stage).