Uncommon in the Green River Formation, the Notogoneus osculus averages 18 inches with the largest specimen measuring 3 feet. Specimens less than 10 inches are extremely rare. Theories vary regarding Notogoneus. Some Paleontologists believe that this species lived primarily in the rivers and only entered the lake when they either became very large, or when they died. Thought to be a bottom feeder, others believe Notogoneus spent most of its life in the rivers that fed Fossil Lake and only entered the lake during certain seasons when the bottom waters were nontoxic.

This is an average size Noto, measuring 19 inches on a 20.5 by 29 inch plate. The only flaw on this particular specimen is some slight disarticulation in the head, although it's only a few bones. The body and the fins are in beautiful shape. Submitted by Stone Relic.