Argyll Group and a Scatsta ‘Division’ which equates to the Appin Group. Though now metamorphosed, the Dalradian sequence was originally deposited as marine sands and muds, silt and limestone. Metamorphism has been low to medium grade for the most part and resulted in the formation of slates, phyllites, psammites, pelites and semipelites. The Tayvallich Subgroup contains volcanics within a turbidite basin and there are lavas within the overlying Southern Highland Group. Southern Highland Group The Southern Highland Group is found along the entire southeastern margin of the Grampian Highlands from Kintyre to Stonehaven and also in the northeast along the coastal strip between Fraserburgh and Portsoy, extending south to the Don valley. In Shetland, the Clift Hills Division extends from north of Lerwick south to Fitful Head. In Ireland the most extensive outcrop of the Southern Highland Group is to the north and south of Lough Foyle and west to Lough Swilly. Smaller exposures occur as far to the southwest as Inishbofin, County Galway. Argyll and Appin groups In mainland Scotland, the Appin and Argyll group sequences occupy the intermediate ground between the Southern Highland and Grampian groups. The Argyll Group is divided into four subgroups, thus: Tayvallich Subgroup Crinan Subgroup Easdale Subgroup Islay Subgroup whilst the Appin Group is divided into three subgroups: Blair Atholl Subgroup Ballachulish Subgroup Lochaber Subgroup In Shetland the Whiteness ‘Division’ forms the core of Mainland whilst the Scatsta ‘Division’ forms the western halves of Unst and Fetlar, all of Whalsay and much of the southeastern part of Mainland, east of the Nesting Fault. These rocks are also present in Ireland across County Londonderry and County Donegal and appear again in the Ox Mountains, the Nephin Beg Range and the Twelve Pins of Connemara. Grampian Group The Grampian Group rocks occupy the ground south west from Elgin and extending down the Great Glen as far as Corran on Loch Linnhe and, further east, as far south as Tyndrum. It is divided into three subgroups: Glen Spean Subgroup Corrieyairack Subgroup Glenshirra Subgroup Shetland sequence The stratigraphic position of the sequence identified as Dalradian in the Shetland Islands is uncertain, because the main marker within the sequence in Scotland and Ireland, the Port Askaig Formation tillite, is not present. Carbon isotope data from four metamorphosed limestones within this mainly siliclastic sequence, suggest that the entire Shetland sequence probably lies stratigraphically above the tillite marker, explaining its absence.