In 1807 Thomas Jefferson sent General George Rogers Clark to Big Bone Lick, Kentucky, to collect fossils. The site of an ancient salt lick, the Kentucky site had once attracted Pleistocene-era mammoths, giant ground sloths and giant bison, which had died near the salt lick when they became trapped in the surrounding bogs, leaving a rich heritage of fossils. In his letter of 1807, Jefferson requests that General Rogers have the bones that Rogers had collected packed and shipped to a New Orleans collector, who would then forward them to Washington. In a letter written the next year, 1808, Jefferson described to the French naturalist Bernard Germain de Lacépède the details of Clark's expedition, and offered the bones and other examples of American fauna to the National Institute of Paris.