Big Bone Lick was discovered in 1739 by French Capt. Charles Lemoyne de Longueil. Early explorers found countless bones and teeth of extinct Pleistocene elephants, the mammoth and the mastodon. This saline-sulphur spring was popular for salt making until 1812 and also served as a health resort from 1815-30, with waters noted for mildly curative qualities. Robert Smith, an Indian trader, recognized the significance of the large bones. From 1751-80, Big Bone Lick had many visitors, including Christopher Gist, John Finley, Mary Ingles, John Floyd, and the McAfee brothers. Thomas Jefferson sent an expedition headed by Wm. Clark to collect bones, and the next largest collector was N. S. Shaler. Some tusks measured 8-10 feet long.