Fichier:Guettard-Buache-1752-carte canada louisiane.png

English: First geological map of North America, by Jean-Étienne Guettard and the cartographer Philippe Buache. Title: Mineralogical map, where one sees the nature of lands of Canada and Louisiana. Drawn by Philippe Buache of the royal Academy of sciences, upon the researches and for a memoir by Mr. Guettard of the same academy, 1752. Published in Mémoire dans lequel on compare le Canada à la Suisse par rapport à ses minéraux, 1752, p. 189-220 ("Memoir in which Canada is compared to Switzerland in regard if its minerals").
A belt of marl and clay extends from the Gulf of Mexico to Cape Breton Island, and thence inland toward Quebec. Between it and the coast is a sandy belt, and west of it a schistose and metalliferous belt. Different signs and annotations indicate the places where rocks and minerals were reported between the Atlantic Coast and the Rocky Mountains. Aside from this primitive effort, the first geologic map of the United States is that published by William Maclure in 1809, of which a revised version appeared in 1817.