Wunitang Fm

The type section of Wunitang Formation, the Wunitang section, is located at Baisha Village in Huaqiao Township, about 23 km northeast of the seat of Huaihua City, western Hunan Province. It was measure by Hunan Regional Geological Survey Team in 1972. The Wunitang Formation was first published by Zhang (1997). The name is derived from Wunitang in Baishaxi Village, Huaqiao Township, Zhongfang County, Huaihua City, western Hunan Province. It was originally appeared in a 1986 manuscript by the Hunan Regional Geological Survey Team.

Synonym: （污泥塘组）

The Wunitang Formation is a sequence in alternation of carbonate and clastic rocks. Lower part of the formation consists of greyish black, platy carbonaceous shale, alternated with thin-bedded, laminated dolomitic limestone or crystalline limestone, and with a layer of dark grey and greyish black, thin-bedded, laminated dolomitic limestone, 16.7 m thick, at the base, and a layer of carbonaceous platy shale, 27.9 m, at the top. Middle part consists of dark grey, greyish black, thin- to thick-bedded dolomitic limestone, alternated with thin-bedded siliceous and carbonaceous shale with limestone lenses and platy shale. Upper part consists of greyish black marlstone, intercalated with thin-bedded dolomitic or crystalline limestone and limestone with cherty nodules. The platy carbonaceous shale commonly bears pyritic grains, nodules and stratoid bands. In the type section, the Wunitang Formation is 223.4 m.

In the type section, Wunitang Formation yields only sponge-spicules Protospongis sp. in its upper part. In other sections, the basal part of the formation yields polymerid trilobites Micmacca cf. elongate, Probowmania sp., and Redlichia chinensis; the middle part of the formation yields polymerid trilobites Centrapleura sp., Dorypyge richthofeni, Fuchouia sp., Kootenia sp., Ptychoparia sp., and Solenoparia sp., and brachiopod Eoorthis sp.; the top part of formation yields agnostoid trilobites Lejopyge armata.