The Lower Silurian is divided into the Longmaxi， Dazhongba and Ziyang Stages. The sedimentation is continuous within these stages in northern Guizhou Province. The central and southeastern Guizhou Province， however， was uplifted and became a land during the Longmaxi Age and early Dazhongba Age in Early Silurian， which resulted in a stratigraphic gap. The fall of sea level made the LowerMiddle Ordovician experienced exposure and a karst landform was formed. With the line from Yuqing to Huangping， the uplifting area is divided into two parts: northern area and southern area. In the southern area， the Wengxiang Formation(or the Gaozhaitian Formation)of the Ziyang Stage unconformably overlaps on the exposed surface from south to north. Bay and lagoon calcareous sandmudstone deposits were dominant in the KailiDuyun region， while in the Guiyang region open shoreshallow marine deposits were developed. During this transgression in the Early Silurian， the underlying karst and weathered crust were reworked. The wavereworked calcirudite and transgressionfilled limestonebearing gravely clastics were deposited， neither of which belonged to the basal conglomerate.
HU Xiao-Song,LIU Wei,ZHOU Di-Kang et al. Sedimentary facies of the Lower Silurian in central and southeastern Guizhou Province[J]. JOPC, 2009, 11(1): 12-19.
