The lost ancient ocean (Palaeo Tethys) appeared around 395 million years (Devon Period) and then disappeared around 215 million years ago (Triass Period). The lost ancient ocean trail was characterized by the Indochina plate in the east as the northern side of Gondwana and Sibumasu in the West. Then this plate recorded the events of ancient volcanoes forming eugosyncline as a result of subduction zones representing the expansion of the Palaeo-Tethys Ocean (Zahirovic et al, 2014). Ancient volcanic arcs stretched along Peninsular Malaysia to Belitong which opened 15 km wide in Siantu (Osberger, 1968). Medium volcanic rocks to acids occured in the Early Permian, while, most of the content of acidic volcanic rocks were Triass (Metcalfe et al, 1982). These eruption products were associated with sea water as a spillite in the form of a pillow, solid, and contain plagioclase, pyroxene, and chlorite (Subang, 1996).This world-class geological heritage can be found in the Lava Bantal Siantu Geosite.