From the album: ECHINOIDS & OTHER INVERTEBRATES
Mississippian blastoids (Pentremites sp.) from the Ridenhower Fm, Upper Paint Creek Group, near Milstadt, Illinois. The larger blastoid is 12.0mm tall.
The brachiopod is Spiriferina spinosa (Norwood & Pratten). Notice the net-like bryozoans on the matrix.
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© Harry Pristis 2013