Comparison of the distributions of shell assemblages and living molluscan populations in Liverpool Bay, indicates considerable offshore and onshore transportation of shells and preferential accumulation in the intertidal zone. The different depths from which moribund and empty shells are derived suggest two separate modes of transportation. Instantaneous transportation occurs in short, infrequent periods of high energy conditions at the sediment/water interface and produces high density, low diversity shell assemblages. Progressivc transportation occurs more frequently and produces low density, high diversity shell assemblages. A systematic list of the marine Mollusca of collecting areas in Liverpool Bay is also presented.