I always like large brachiopods and these specimens of Postepithryis cincta certainly meet that standard. The specimens below are roughly 1.5" long (4cm) by 1.25" wide (3cm). They come from rocks dated to the Oxfordian stage (Jurassic) near Bourges in the department of Cher, France.
P. cincta is a Terebratulid type brachiopod, oval shaped and with a large foramen (round hole) in the umbo (beak like extension of the shell) where the pedicle muscle once extended. The only other distinguishing feature is the gentle, sine wave like shape to the anterior margin where the two shell halves meet.
Thanks to Gery for these fossils!