Studied the Early Cambrian trilobite faunas collected from Yangjiapingin of Shimen County
Hunan Province
four fossil zones(assemblages)have been established such as Hunanocephalus zone
Arthricocephalus zone
Megapalaeolenus-Palaeolenus zone and Probowmania-Yuehsienszeella assemblage.According to the analysis of the Early Cambrian paleobiogeography of the research area
Yangjiaping biogeographic area should belong to Yangzi biotic province ever since late Canglangpu age
and six communities such as Hunanocephalus community
Arthricocephalus community
Redlichia takooensis community
R.hupehensis community
Palaeolenus community
Redlichia-Yuehsienszeella community have been established.This thus renewed the tranditional view of the area being a transi-tional biogeographic area in Early Cambrian.