1Caspar Wistar to Thomas Jefferson, 27 April 1815 (Jefferson Papers)
fossils; study of [index entry]
2José Corrêa da Serra to Thomas Jefferson, 16 June 1816 (Jefferson Papers)
fossils; study of [index entry]
3Henry R. Schoolcraft to Thomas Jefferson, 5 January 1822 (Jefferson Papers)
fossils; study of [index entry]
4Thomas Jefferson to Henry R. Schoolcraft, 26 January 1822 (Jefferson Papers)
fossils; study of [index entry]