Stratigraphy: Jurassic volcanic rocks with an age of approximately 146.6 ± 0.2 million years before present.

Distribution: The Lai Chi Chong Formation crops out north of the Chek Keng Fault in the northeastern New Territories.

Lithology: Dominantly coarse ash crystal tuff with intercalated mudstone, tuffaceous sandstone, rhyolite lava and minor conglomerate.

(Flame structures in the Lai Chi Chong Formation, Lai Chi Chong, northeastern New Territories)