THE northern sheet of “The Map of Britain in the Dark Ages” (Ordnance Survey Office, Southampton, 1939. Pp. 43. Price 5s. net) is, if possible, of even greater interest than the southern sheet issued by the Ordnance Survey in 1935. This is not least, perhaps, because it serves to emphasize the imperfections in the material, while affording suggestion of the more urgent provinces to which further research should be directed, if any substantial advance in knowledge is to be made. Thus, for example, brochs and earth-houses do not appear here, being reserved for future separate treatment, owing to the difficulty of determining their chronological relation to the period covered by the map. This period, roughly, is from A.D. 440 to 840, an approximation to the date of the union of the kingdom of Picts and Scots under Kenneth, son of Alpin. In regard to technical details, the scale of the map is 1: 1,000,000. The practice in the use of symbols of archaeological maps previously issued by the Survey is maintained, the form of the symbols suggesting the objects, additions being made to the symbols already in use as required, as, for example, in indicating the distribution of Pictish symbols. An expository introduction deals with certain broad questions-the extent and location of the British, Scottish, Pictish and Anglian regions, the distribution of tribes, the lines of early roads, and the like. The section in which the roads are traced is a particularly instructive synthesis of geographical and archaeological argument, although the editor modestly disclaims any attempt at original research and professes to do no more than record existing knowledge. The discussion of the range of distribution of the ethnic groups brings out very markedly the need for both a systematic survey of Scottish place names and of systematic excavation, directed to specific ends, mainly chronological.