Nautilidae, both surviving and extinct, are characterized by spiral-like shells that are generally smooth, w/whorl sections. Nautiluses represent the only living members of Nautiloidea, and are often considered "living fossils," fossil records indicating that nautiloids have not evolved much during the last 500 million years. We are offering a polished nautilus fossil that was found in Erfoud, Morocco, which is in the Sahara Desert region. It dates to the Devonian Era, some 350 million years ago. It's structures have been replaced by marble over the millenia, nicely showcasing the chambers within the nautilus' shell. The fossil measures 8.5x11.25x2" thick and weighs just over 8 lbs.