Here is another of the mysterious Brachipods from the Waldron Shale. I think this is a Rhynchotreta sp. shell based on this post by Mike at Louisville Fossils and Beyond.
As you can see, it is very long and narrow which may mean it's not Rhynchotreta but I'm not sure. One of the neat anatomical features of this shell is the fact that the brachial valve ends well before the pedicle valve does to allow the pedicle space to stick out (the small round hole).