Stratigraphy: Late Cretaceous post-volcanic sedimentary
rocks.
Distribution: The Port Island Formation
is only exposed on small islands in Mirs Bay including Port Island,
Round Island, Channel Rock and Shek Ngau Chau.
Lithology: Reddish-brown thickly bedded
conglomerate and sandstone, with thinly bedded reddish siltstone.
Depositional Environment: The sedimentary
rocks of the Port Island Formation are interpreted as distal alluvial
fan or proximal braidplain deposits.
(Thickly-bedded volcanic conglomerate and sandstone of the Port Island Formation, Port Island)
