Firth locally the change is held to be at the Tail of the Bank where the river crosses a sandbar off Greenock at the junction to the Gare Loch, or even further west at Gourock point. However, some firths are exceptions. The Cromarty Firth on the east coast of Scotland, for example, resembles a large loch with only a relatively small outlet to the sea and the Solway Firth and the Moray Firth are more like extremely large bays. The Pentland Firth is a strait rather than a bay or an inlet. These are connected to, or form part of, the
Pentland Firth Pentland Firth The Pentland Firth (, meaning the Orcadian Strait) is a strait which separates the Orkney Islands from Caithness in the north of Scotland. Despite the name, it is not a firth. The name is presumed to be a corruption of the Old Norse "Petlandsfjörð", meaning "the fjord of Pictland", and is completely unrelated to the Pentland Hills near Edinburgh. Prior to the Norse occupation of Orkney the strait was known as the "Sea of Orcs" – a reference to the Pictish tribe who inhabited Orkney. Such was their marine prowess that there are also instances of this name