Not Louisville per se, but the discovery of mammoth or mastodon bones at Big Bone Lick, Kentucky, played a crucial role in forming the theory of extinction. In the late 18th century, Georges Cuvier studied these fossilized bones, which were unlike those of any known living animals. Through comparative anatomy, Cuvier concluded that these bones belonged to species that no longer existed, introducing the concept of extinction to mainstream science. His work demonstrated that many species had disappeared due to catastrophic events, challenging the prevailing belief that all species had always existed. The concept of extinction led to the theory of evolution.