As the first sediment in Cenozoic time in Ningxia region, the Eocene Sikouzi Formation has special tectonic meaning, however, its development has not been interpreted satisfactorily yet.

• 做为新生代宁夏境内的第一套沉积,始新统寺口子组具有其特殊的意义,但一直没有得到满意的解释。