Abstract

The stratigraphy of the Melinau Limestone, a pure shallow-water carbonate deposit in north-east Sarawak with a maximum thickness of about 7000 ft, is described. Dating of this sequence is based almost entirely on larger Foraminifera. The changing faunal succession from Upper Eocene through the Oligocene into the Lower Miocene is described and discussed. The probable conditions of deposition are considered and a correlation between the Melinau Limestone sequence and other limestone successions elsewhere in Sarawak is proposed. The criteria usually used for dating mid-Tertiary sediments of similar type in the Tethyan region are reviewed, and an attempt is made to correlate the Melinau succession with comparable successions elsewhere in Indonesia, the Pacific, India, and the Middle East. One new genus, Wilfordia, and three new species of Foraminifera, Dictyoconus melinauensis, Neoalveolina inflata, and Wilfordia sarawakensis, are described. Dictyoconus is recorded for the first time from strata of Oligocene age.