Biostratigraphy and palaeoecology of Middle and Late Ordovician conodonts from the Hulo and Yenwashan formations, western Zhejiang, south‐eastern China

A total of 5,918 conodonts have been recovered from the upper Hulo Formation and the lower Yenwashan Formation in the Hengdu section, Jiangshan County, Zhejiang Province, south‐eastern China, spanning the interval from the middle Darriwilian to the early Sandbian. Thirty‐three species, belonging to 24 genera, have been identified with three biozones (i.e., the Dzikodus tablepointensis Biozone, the Histiodella kristinae Biozone, and the Pygodus anserinus Biozone) recognized in the region. Using multivariate analysis, the Periodon–Protopanderodus biofacies is recorded from the upper Hulo Formation, and the Periodon–Pygodus biofacies and the Protopanderodus–Baltoniodus biofacies are recorded from the lower Yenwashan Formation. The Periodon–Protopanderodus biofacies and the Periodon–Pygodus biofacies represent a deep‐water environment, such as the margin of the platform and/or slope environment, deeper than that of the Protopanderodus–Baltoniodus biofacies.