The lovely large brachiopod below is a Whitfieldella nitida and came from the Waldron shale of Indiana. The Pedicle valve has an overgrowth of some Bryozoan but the Brachial valve preserves the delicate growth lines.
This specimen came from the Waldron shale of Indiana which is Silurian in age (Wenlock epoch, Sheinwoodian to Homerian stage).
Here is a Whitfieldella nitida from the Irondequoit Limestone, of New York, which lies below the Rochester shale (which is roughly the same age as the Waldron shale). Note the difference in size between that specimen and the one pictured above.
And here is a Whitfieldella sp. from my local Keyser limestone which is a little older (Pridoli to Lochkhovian stage) than the Waldron shale