Stratigraphy: Jurassic flow-banded rhyolite sill with an age of approximately 146.6 ± 0.2 million years before present.

Distribution: The Sham Chung Rhyolite can be traced from Sham Chung southwards to Yung Shue O on the south side of Tolo Channel.

Lithology: Flow-banded porphyritic rhyolite sill.