More frequently, however, the stone is entirely unadorned, as in this example, which, along with [Illustration: Centurial Stone, Cilurnum] the former, was removed from Walwick Chesters to Alnwick Castle. The letter C, reversed thus Ↄ, or more frequently an angular mark resembling the letter V, laid upon its side thus >, is the sign usually adopted for _centuria_, century. Two centurial stones are shewn in the wood-cut introduced in page 190. The upper one, that of Valerius Maximus, was described, a century ago, by Horsley, who found it near Haltwhistle-burn. Afterwards it was built up in a gable of the Cawfield farm-house, against which a coal-shed was formed. Here, though sadly begrimed, it was protected from further injury, until rescued by the present owner of the farm, and safely deposited in the museum of antiquities at Chesters. COINS. [Sidenote: NUMISMATIC REMAINS.] Next in importance to the inscribed stones found on the line of the Wall, the student of history will reckon the coins which the spade and plough of the husbandman turn up in considerable numbers in the mural region. In a rude state of society the commercial transactions of the residents of a district are almost entirely confined to an interchange of the commodities produced by each. A body of soldiery, however, liable to be removed from place to place, and compelled to expend their energies in unproductive industry, are necessarily obliged to resort to the use of money. It is chiefly in the stations where the Roman legions lodged, or on the roads which they traversed, that the imperial coin is found. These metallic pieces, bearing the insignia of Rome, thus become exceedingly important in tracking the march of Roman armies. As works of art, the design and execution of many of them are truly admirable. The copper coins of Hadrian are especially worthy of study. The custom which prevailed during the best periods of the empire, of rendering the circulating medium of the market-place the means of commemorating the leading events of the day, gives them increased value. Were all the other records of Roman story destroyed, its most stirring incidents might be recovered by a careful examination of the coins which the cabinets of the antiquary contain. [Sidenote: COINS.]