The Late M esozoic strata in the Daohugou area of Ningcheng，Inner M ongolia are well developed with richfossils， which are composed of tuffaceous mudstones and siltstones and interbedded with volcanic rocks．Regionally，in the Xitaizi area are distributed Early Cretaceous beds of Yixian Formation，yielding rich fossils ofJehol Biota，such as Lycoptera davidi，Peipiaosteus pani，Yanosteus longidorsalis，Protopsephurus liui(fishes)and Confuciusornis sanctus(birds)．In the Daohugou area，however，are distributed Middle-Late Jurassicstrata of Tiaojishan Formation，yielding very rich fossils of Daohugou Biota，such as Jeholotriton paradoxus andChunerpeton tianyiensis (salamanders)， Jeholopterus ningchengensis and Pterorhynchus wellnhofe~i(pterosaurs)， Scansoriopteryx hefmanni and (?) Pedopenna daohugouensis (Maniraptora， theropods)，Mesobaetis sibirica，Mesoneta antiqua，Rhipidoblattina (Canaliblatta)hebeiensis，Brunneus haifanggouensis。Palaeontinodes haifanggouensis and others (insects)， Euestheria ziliujingensis， E． haifanggouensis． E．jingyuanensis and E． 1uanpingensis (conchostracans)， Cladophlebis (Osmunda ?) sp．， Anomozamitesangulatus，A．(Trymia?)sp．，Cycadolepis sp．，Ginkgoites sp．，Pityospermus sp．，Pityocladussp．，Zamitesgigas，Yanliaoia sinensis and Coniopteris burejensis(plants)．According to our current study，Daohugou Biota issurely considered to be of an age of Middle- Late Jurassic (Callovian- Oxfordian)， rather than EarlyCretaceo1ElS．