Age: Green River Formation, Eocene Period. Era : Eocene. These skeletal remains can be slightly incomplete or not overly recognisable as to the what way the fish is laying etc. so the preparers will paint the piece with a brown stain to give a protective layer, and to help highlight the correct position of the fish, and it is not uncommon for them to paint where the fins etc would have been so to portray what the actual fish would have looked like.
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