Johann Jacob Baier (14 June 1677– 14 July 1735) was a German physician and naturalist who wrote on the geology and fossils of the Nuremberg area in his book Oryctographia Norica. He considered the Deluge of the Bible to be the only catastrophe to have occurred in earth history. His specimens are distributed in collections. A specimen of the ammonite Phylloceras heterophyllum was purchased by the Jena museum in 1728.