Unluckily Lafitau had in his head a preconceived theory on the mythology, manners, institutions & governments of the antient nations of Europe, Asia, & Africa, and seems to have entered on those of America only to fit them into the same frame, and to draw from them a confirmation of his general theory... He selects therefore all the facts and adopts all the falsehoods which favor his theory, and very gravely retails such absurdities as zeal for a theory could alone swallow. He was a man of much classical & scriptural reading, and had rendered his book not unentertaining… but collects his matter much more from the writings of others, than from his own observation.

(TJ to John Adams, June 11, 1812.)
http://lcweb2.loc.gov/cgi-bin/ampage?collId=rbc3&fileName=rbc0001_2007jeffca...