Brachiopod?

[Agassiz]

Hi folks, would love help with a fossil ID. Specimens were found in one piece of loose rock, on the banks of the Otter Tail River, Fergus Falls, MN. I'm guessing it's a brachiopod of sorts. Not sure how to determine the period it came from as this is not from an outcrop here, and we're situated on glacial till and granite. It looks somewhat like pentamerus oblongus? Anyways, any help appreciated!

[aek]

No Silurian rocks in Minnesota. Not sure what it is.

[Agassiz]

Thank you, aek! I'm glad to be learning.