German geologist, a pioneer in the development of stratigraphy, the study of rock strata.

Füchsel began medical practice in 1756 and the following year was appointed to organize the natural science collections of Friedrich Carl, later prince of the German principality of Schwarzburg-Rudolstadt, where Füchsel became court physician (1767) and librarian (1770). The originator of the idea of stratigraphic formations, he was one of the first actually to make recorded measurements of sections of stratified rock. He also made the first geological map of Germany and adjacent areas.