Late Roman Scotland is a particularly frustrating period to look at: the archaeology is vague and the literary sources are few and far between. It is fair to say that after the invasions of Septimius Severus the best that can be hoped for are a few lines here and there.
Nice to see at Past Horizons a press release about Rampart Scotland's (ongoing) dig at Sherrifside, east of Edinburgh. Keyhole excavation in 2012 uncovered a massive 9 metre wide and 3 metre deep ditch which was constructed after 360AD.
For obvious reasons there is an enthusiasm to link this to the ‘barbarica conspiratio’ mentioned by Ammianus Marcellinus (27.8; 28.3). The best article on that is R. C. Blockley's, "The Date of the 'Barbarian Conspiracy" Britannia 11 (1980), pp. 223-225
The link is not totally implausible. What is now Scotland had not been totally abandoned by this time. As I mentioned back in November, an ae of Magnentius, which dates to AD351, has been found at the Bearsden Bath House on the Antonine Wall.