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
Architecture of Scotland in the Roman era period. There is also evidence of distinctive stone wheelhouses and small underground souterrains. From about 71 CE the Romans began military expeditions into what is now Scotland, building forts, like that at Trimontium, and probably pushing north as far as the River Tay where they created more fortifications, like those at Inchtuthil. These were soon abandoned, and the Romans settled for the occupation of the Southern Uplands by the end of the first century, below a line drawn between the Tyne and Solway Firth. This resulted in more fortifications and the building of Hadrian's Wall across what is now northern