The Ordovician Period is the second period of the Palaeozoic Era and extended from 488 to 444 million years ago, a duration of 44 million years. The Ordovician Era was first proposed in 1879 by C. Lapworth. The Ordovician System includes the rocks that formed during the Ordovician Period. The Ordovician System was first studied in Britain, and it was divided into six stages according to graptolite fossils. Currently, it is globally subdivided into three series and seven stages, and three stages have been established in China. The Middle Ordovician turtle crack limestone is the base material that forms the Xingwen ‘Taianwu stone forest landscape’.