1Thomas Jefferson to William Brown, 10 September 1809 (Jefferson Papers)
Clark (Clarke), William; sends fossils to TJ [index entry]
2Burwell Bassett to Thomas Jefferson, 20 July 1811 (Jefferson Papers)
Clark (Clarke), William; sends fossils to TJ [index entry]
3Caspar Wistar to Thomas Jefferson, 27 April 1815 (Jefferson Papers)
Clark (Clarke), William; sends fossils to TJ [index entry]