In the second half of the 19th century, near the Veneto towns of Libàno and Bolzano Bellunese, stood some quarries from which abrasive sandstone was obtained to produce the grinding wheels used by knife grinders to sharpen the blades of knives. This rock dates back to the Early Miocene and is between 23 and 16 million years old. Several fossil vertebrate remains have been found here, including many largely dolphin-like cetaceans. The Miocene marine life of Belluno is an extraordinary example of biodiversity, as it comprises as many as six families, five of which are now extinct. Two of these (the Dalpiazinidae and the Eoplatanistidae) are present exclusively in these deposits. These are primitive cetaceans with an elongated snout, very similar to those inhabiting the coastal waters of river deltas, such as that of the Ganges and the Indus.
