We are told in the History of Carausius, that he repaired the _prætentura_ made in Scotland by Agricola, and added seven forts to it: a wise and politic prince knew the necessity of it; and consequently infer we, that he as surely repaired the Carsdike navigation, to supply the soldiers with corn, in that northern situation: and I have several reasons to induce me to conclude, he not only did so, but carried it further southward than before, viz. from Peterborough quite to Cambridge; some of which reasons I shall recite in the history of that hero. At present I shall only hint, that his name has ever been affixed to this famous canal, which has never been regarded by writers. It is of utmost importance in the knowledge of Roman antiquity; and it is an affair of such public emolument, as not to be unworthy of the notice of the legislature; where an inland water-carriage is made, for 200 miles in length, from Cambridge to Boroughbridge. The Roman provinces, as we find them in our map, are these. _Maxima Cæsariensis_, or _Brittania superior_, chiefly the country of the Brigantes, conquered by Cerealis, and so named by him, in the beginning of Vespasian’s reign. _Valentia_, all that country comprehended between the two _Prætentura_’s. _Brittania prima_, or _inferior_, that part of the island south of the Thames. _Brittania secunda_, being Wales. _Flavia Cæsariensis_, that part between the Humber and the Thames; denominated from the family-name of Vespasian. _Vespasiana_, that part of Scotland between the _Varar Æstuary_, or highland boundary, and the northern _Prætentura_. Lastly, _Caledonia_ properly, or the Highlands, which the Romans never conquered; and that part called _Vespasiana_, after Agricola returned, was neglected by Domitian, and recovered by the Scots; at least, to the first _Prætentura_: and it is from Richard of Cirencester alone, that we have an Itinerary of it from the _Vararis Æstuary_, on which is the last Roman station, called _Alata castra_, now Inverness. I shall next recite all the places, rivers, mountains, &c. specified in our map, the provinces they are in, and _that_ in alphabetical order; together with the modern names of each, according to the best of my knowledge; whereby the value and excellence of our manuscript will more easily appear; seeing so many of them we were hitherto unacquainted withall, which I shall mark particularly thus *, as also those wherein we are able to correct former writers. Places mentioned in the Map.