Anak Tikus (Baby Rats) Island is a remnant island located at the southernmost tip of Langgun Island. It is very rich in fossils.
This remnant island is made of dark coloured, moderate to thickly layered limestone representing the Early Ordovician Lower Limestone Member of the Setul Formation. This limestone is very rich in fossils, particularly gastropod and cephalopod.
Among most common gastropods are Malayaspira rugosa, Teichispira kobayashii, Helicotoma jonesi, Palaeomphalus giganteus, Lesuerilla zonata and Hormotoma sp. This island was formed as a result of prolonged erosion and solution along weaker zone on the neck of an ancient headland.
