History of Workington established on the north bank of the mouth of the River Derwent, near present-day Siddick Pond and Northside. Another fort or watchtower would have been on How Michael to the south side of the river, near present-day Chapel Bank. In 122, the Romans begin building Hadrian's Wall from Bowness on the Solway Firth to Wallsend on the North Sea. The discovery of a Roman fort around the parish church in Moresby to the south, and fortifications to the north at Risehow (Flimby), Maryport and Crosscannonby support the argument that the coastal wall extended down the whole Solway coast and formed
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