Eoliths can be found by petitioning the Dean for new experiments from your lab. You need to have a bottle of Absinth and not have any bones/eoliths already. Another source is the Rubbery from the Bone Market. You need to complete “accept a paleontological task from the Dean” to find the route and then take the option to travel from the Dept. of Menace Eradication. (You’ll need to have at least 3 Bizzare for the Rubbery to show up in the deck there).