Abstract: The present paper deals, in details, with a stratigraphic section (formerly Matuo Formation) in the Yanshiping region, Qiangtang, which may be assigned to the Qoimaco Formation in the light of rock (associations), and to the early Bathonian (Middle Jurassic) according to organic fossils in the strata. The sedimentary facies analysis shows that the strata within the section belong to the delta and tidal-flat deposits. The palaeontological and palaeoecological data indicate that these strata were deposited in a brackish environment, with the sea water deepening upwards.