1Thomas Jefferson to Pierre Samuel Du Pont de Nemours, André Thoüin, and Bartelémy de Faujas-Saint Fond, 16 May 1809 (Jefferson Papers)
geology; scholars of [index entry]
2Thomas Cooper to Thomas Jefferson, 10 May 1810 (Jefferson Papers)
geology; scholars of [index entry]
3Thomas Jefferson to Silvain Godon, 21 May 1810 (Jefferson Papers)
geology; scholars of [index entry]