"His unstoppable curiosity triumphed, and Leonardo went into the cave. There he discovered, embedded in the wall, a fossil whale. "Oh mighty and once-living instrument of nature," he wrote, "your vast strength was to no avail."26 Some scholars have assumed that he was describing a fantasy hike or riffing on some verses by Seneca. But his notebook page and those surrounding it are filled with descriptions of layers of fossil shells, and many fossilized whale bones have in fact been discovered in Tuscany.27 The whale fossil triggered"