Chemostratigraphical correlation provides valuable insights into the status of the Colonsay Group, which field and structural studies have left unresolved. Using published discriminant functions, major and trace element data support previously proposed correlations of the Colonsay Limestone with Appin Group (Lower Dalradian) limestones, and particularly with the Ballachulish Limestone Formation. They also tend to preclude correlations with other nearby Dalradian carbonate formations, with marbles of the early Precambrian Lewisian complex, and with miscellaneous unassigned limestones in a similar structural position to the Colonsay Limestone, astride the Great Glen fault.
