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The Surma group of rocks are well-exposed in the steeper and faulted western flank as well as gentle and wider eastern flank of the asymmetric doubly plunging Sitakund anticline under the Chittagong district from Bariyadhala in the north to Barabkund in the south, which trends regionally in the NNW-SSE directions. Lithostratigraphically, the Bhuban formation consists of alternation yellow to yellowish gray medium to grained sandstone with black shale and siltstone, Boka Bil formation constitutes the medium grained yellow to yellowish gray sandstone-siltstone with bluish gray shale. Eleven facies have been identified with the lithosuccession of this group, which are grouped into turbidite facies association, deep marine basin plain and tide-generated facies association. The sub facies association of tide-dominated delta, estuarine, tidal creek/small estuarine and mud-dominated tidal flat constitute the tide generated facies association. Five parasequences are delineated. The overall depositional environments of the study area vary from deep marine to submarine fan in the Bhuban formation and tidal delta, estuarine channel and tidal flat in the Boka Bil formation at various phases during deposition due to relative sea level rise and fall, sediment supply and basin tectonics. [ABSTRACT FROM AUTHOR]