No 1. Pl. XXI. is an exact representation of the front of a Roman altar found in Tinmouth Castle in Northumberland, by Major Durnford, at the depth of six feet in the earth, where it had been laid as a foundation stone, probably of the antient Christian church which is said to have been erected there soon after the introduction of that faith into Britain. The lower part of it, by whatever accident, is much defaced, and it is at present quite flat at the top, though we may suppose it to have had originally a focus there, which the workmen, in order to make it square and bed properly, may have been obliged to take off. The inscription is plainly to be read : “Jovi optimo maximo “Ælius Rufus Præfectus Cohortis quartæ Lingonum.” The Lingones were a people of Champagne in France, and are well known to have been among the Roman auxiliary troops of infantry, but this is our first information where the fourth Cohort of them was stationed in Britain.