Bulletin of the Geological Society of Malaysia, Volume 19, April 1986, pp. 183 – 191
CCOP-ESCAP, UN Building, Bangkok, Thailand
Abstract: Lower Permian corals (Protomichelinia, Kepingophyllum, Chusenophyllum? and Polythecalis) are for the first time recorded from Sumatra. These corals are associated with fusulinids indicative of the Middle-Late Asselian, Pseudoschwagerina Zone. Lower Permian sediments appear to be widely developed in the upper Mesumai River area and appear to represent a forested volcanic arc surrounded by a shallow muddy sea.