. "Ellis Formation"@en . . . . "43256320"^^ . . "1200"^^ . . . . . . . . . "1096200404"^^ . . . . . "The Ellis Formation is a geologic formation of the Ellis Group in Montana. It preserves fossils dating back to the Jurassic period."@en . "Ellis Formation"@en . . . . . . . . "The Ellis Formation is a geologic formation of the Ellis Group in Montana. It preserves fossils dating back to the Jurassic period."@en . . . . . .