(CNN) — Scientists believe a fossil found at a landfill in California belongs to an extinct species of whale that lived between 4 and 7 million years ago.

The seven-ton fossil was unearthed in June during a construction excavation at the Prima Deshecha landfill in San Juan Capistrano, Orange County Waste & Recycling announced in a statement.

A paleontologist with Paleo Solutions Lab, a company employed by the County of Orange —paleontologists must monitor construction excavations under California law — was working at the site when a large bone was spotted.

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