The Read Bay Formation at Cape Admiral M'Clintock, Somerset Island, consists largely of thick units of rubbly argillaceous limestone separated by thin units of shelly limestone, intraclastic shelly limestone or intraformational conglomerate. The latter units are random in occurrence as demonstrated by Markov Chain Analysis, and represent brief periods of deposition in high energy regimes. The rubbly argillaceous limestone units are consistently thicker and represent relatively longer periods of deposition in lower energy regimes. The random deposits appear to have been storm generated, their varied content of shelly and intraclastic debris probably reflecting various combinations of basin physiography, wind strength and wind direction. The rocks were deposited in both intertidal and subtidal environments. The intertidal sequences include numerous vertical facies changes (alternation of thin units of rubbly argillaceous limestone and the random units) whereas the subtidal sequences have fewer facies changes (alternation of thick units of rubbly argillaceous limestone and the random units). The intertidal rocks contain no fauna, a brachiopod fauna of low diversity or a brachiopod-gastropod fauna of low diversity whereas the subtidal rocks commonly contain a rich, diverse in situ fauna of brachiopods and corals.