The Trachyceras aon produced in Yunnan, with surrounding rocks, have been cleaned to keep the details intact, and the lines of the ammonites can be clearly seen. There are also large brachiopods on the matrix. Group fossils are generally rare. What makes this fossil so rare is that it has fossils on both the front and back sides. Name: Trachyceras aon Origin: Yunnan, China Age: Triassic Specifications: Matrix 24.5*19.3*3 cm