The 4-foot-wide clam is on display at the College of Eastern Utah's Prehistoric Museum in Price.
KSL-TV reports that museum officials dug the dinner table-sized clam out of sandstone on the edge of the Book Cliffs in Emery County last year.
Museum director Kenneth Carpenter says there's nothing nearly as big as this clam living today.
It would make for a lot of clam chowder, but officials say the prehistoric clam had a defense mechanism against predators that made it taste sulfurous.
Carpenter believes the same dig site is hiding even bigger clams -- possibly 6 feet wide.
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