Through time, the excavation and earth quarries activities have been increased rapidly and this process also occurred at Pokok Sena, Kedah. Due to this activites, the study on the sedimentary depositional processes which related with Mahang Formation, Kubang Pasu Formation and Semanggol Formation is achievable. The research is intended to discover the boundary that have been separated the three formations. The localities visited for this research are Kg. Kebun 500, Kg. Jabi, Wood Factory area, Kg. Rambutan, Bukit Barak Quarry and Bukit Tembaga. The localities are believed to be part of chert unit and might be part of rhythmite unit. Through the visitation, the main lithofacies found are bedded chert, black mudstone, interbedded sandstone and shale, siliceous shale, interbedded chert and shale and massive sandstone. There are some turbidite deposits such as load casts and mud clasts. Observing the distribution of the lithology deposited within the research study area, it can be suggested that the depositional setting is deep marine environment. The presence of turbidite deposits might due to the turbidity currents that existed during the deposition of the rhythmite unit. This comes to the preliminary conclusion that the research study area is near to the rhythmite unit area. However, more study need to be done to define the depositional process accurately. The preliminary results are recorded using the sedimentary loggings. © 2019 EAGE-GSM 2nd Asia Pacific Meeting on Near Surface Geoscience and Engineering.All right reserved.