Stratigraphy: Cretaceous volcanic rocks with an age of approximately 142.8 ± 0.2 million years before present.

Distribution: The Mount Davis Formation crops out in the northwest and the east of Hong Kong Island, eastern Kowloon, and two areas in the eastern side of the Sha Tin Valley.

Lithology: Dominantly coarse ash crystal tuff with intercalated tuffaceous siltstone and sandstone.

(Coarse ash crystal tuff of the Mount Davis Formation, Mount Davis, northwestern Hong Kong Island)