The early cretaceous sedimentary sequence of Gagau Group exposed along the upstream of Sungai Chichir comprises of massive pebbly sandstone, massive mudstone and thickly bedded sandstone with various sedimentary structures and fossils. This sequence can be divided into seven sedimentary facies with different mechanism of sedimentation. Based on association between various sedimentary facies it can be interpreted that this sequence was deposited in various aluvial plain environment including main river channel, meandering rivers, braided river and flood plain. Fossils discovered give an early cretaceous age to the sequence. Evidence of top-soil give a good prospect of finding better and more complete terrestrial fossils, especially vertebrate fauna and dinosaurs. © 2017 Penerbit Universiti Kebangsaan Malaysia. All rights reserved.