This tiny fossil brachiopod is called Amboecoelia unbonata and is a common fossil from the middle Devonian period. It has a classic lamp shape to the shell with a convex pedicle valve and a nearly flat brachial valve. In the Windom shale at Deep Springs Rd. it is most often found disarticulated, only one valve is present. Maybe the preferred environment that it liked to live in was elsewhere and currents or storm event washed shells in? Typically a fossil of A. umbonata is about 1cm in size.
Specimen #1 - Pedicle valve
Specimen #2 - loose pedicle valve (brachial valve view)
Specimen #3 - Another pedicle valve (they seem to dominate what is found because they stick out compared to the flat brachial valve)
Specimen #4 - A brachial valve (finally!)
These specimens were found at a borrow pit on Deep Springs Road in Madison County, NY which exposes the Windom shale member of
the Moscow formation (middle Devonian in age, Givetian stage.)