After restudying the 10 sections of the bottom boundary of the Wenlock Series in the Ziyang area, the writers suggest that the standard fossil Oktavites spiralis (Geinitz) of the late Llandovery has never entered the Wenlock. This conclusion is consistent with the international view. All the fossils which were identified as C. centrifugus Boucek in the Ziyang area should be changed to C. annularis Fu, and they all occur in the C. lapworthi biozone. In recent years authentic specimens of C. centrifugus Boucek and C. murchisoni Carruthers have been collected in Ziyang, which will substantiate the cyrtograptid succession process of C. lapworthi-C. sakmaricus-C. insectus-C. centrifugus-C. murchisoni.