Stratigraphy: Cretaceous dykes intruding the Chi Ma Wan and South Lamma plutons.

Distribution: The Shan Tei Tong Rhyodacite dykes occur mostly in a zone extending from the Chi Ma Wan Peninsula, across Lamma Island to southern parts of Hong Kong.

Lithology: Feldsparphyric rhyodacite to porphyritic granite dykes.

(Feldsparphyric rhyodacite dyke (Shan Tei Tong Rhyodacite), Mount Stenhouse, Lamma Island)