怀来县长城系团山子组内发现潜穴

DISCOVERY OF BURROWS IN TUANSHANZI FORMATION OF CHANGCHENG SYSTEM IN HUAILAI COUNTY

A large mount of burrows and bioturbation structures are found in the thin sections of brown dolomite in the Tuanshanzi Formation of Changcheng System, Huailai County, Hebei Province. The bodies of the burrows are small. The maximum length is 5~7mm , d = 2~ 3. 5mm , the minimum length is 2 mm , d = 0. 08mm. The forms are short tubular, conical, earthenware jar or long tubular. The discovery of burrows provides conclusive evidence for the precedence of time of the animal occurrence (about 1 700~1 757Ma).