Shell type?

[Bob Saunders]

Hi all, this fossil hash plate is like a super hard gray mud with cracks. Even using a wood rasp to smooth much off. Mostly a trial or training piece. The shell was broken and in layers, with much covered. I have removed a lot of the cover,  can I get an I'd, and is it worth continuing? I also see two Brachiapods, and they still some material stuck on the surface. I do not know of a way to dissolve the matrix, to recover the fossils. ultrasonic does nothing. 

[Fossildude19]

Possibly a spiriferid. 

More would need to be uncovered to even nail it down to that. 

Many brachiopods have the long, deep growth lines.   

 

You could try 5% acetic acid. (White vinegar) .

That can eat away at the shell material, however, so keep a close eye and neutralize with water between treatments.