RC (MHi); on a sheet folded to form four pages, with letter on p. 1, p. 2 blank, enclosure on p. 3, and address on p. 4; addressed: “Hon. Thomas Jefferson Monticello Virginia”; stamped; postmarked New Haven, 1 Sept.; endorsed by TJ as received 14 Sept. 1819 and so recorded in SJL. Enclosure: “An Act to incorporate The American Geological Society,” approved by the Connecticut legislature on 31 May 1819, noting that “learned societies have been found to promote, preserve, and diffuse, the knowledge of those arts and sciences which are the support of agriculture, manufactures and commerce, and to advance the dignity, virtue, and happiness, of a people”; stating “that George Gibbs, Benjamin Silliman, Parker Cleaveland, J. W. Webster, Robert Hare, Robert Gilmor, Jun. and their associates, be, and they are hereby constituted, a body politic and corporate, by the name of The American Geological Society”; and granting the society the legal rights of incorporation, including the ability to elect officers and members, make bylaws, and hold property not exceeding $60,000 in value (printed text in MHi, with printed signatures of David Plant as speaker of the Connecticut House of Representatives, Jonathan Ingersoll as president of the Connecticut Senate, Oliver Wolcott as governor, and Thomas Day as secretary of state; conjoined with covering letter).