Flint knives, though apparently less abundant than in the different Scandinavian countries, and especially in Denmark, are frequently turned up in the course of agricultural operations. In no instance that has come under my notice have implements been found in Scotland exactly resembling the curious lunar flint knives and saws of such common occurrence in Denmark and Sweden; yet examples of similar form are familiar to American archæologists among the singular contents of the great mounds explored of late years in the valley of the Mississippi, and in other districts of the North American continent. These are generally made of slate, and stone knives analogous to them appear also to have been used in the Scottish primitive periods, to supply similar necessities. In the Shetland and Orkney islands especially stone knives are common, and in other districts knives of flint, though not of the northern lunar shape, are often met with. It is perhaps of fully as much importance, in the present stage of archæological inquiries, to note the dissimilarity, as the correspondence of relics of the same period in different countries. We have already observed a resemblance so remarkable, in the implements of the Stone Period pertaining to countries alike separated by time and space, as to preclude the possibility of ascribing it to any mutual intercourse or common source of knowledge, that nothing but a correspondence in many minute details will justify the inference of international intercourse or similarity of races. Dissimilarity, however, in these primitive implements, if the means of comparison be sufficiently extensive, may suffice to establish the opposite conclusion, that little or no intercourse had existed between Scotland and those countries, such as Norway and Sweden, at least during the earliest historic periods. Little proof, indeed, is required to establish this--if we set aside the opinion, assumed without any investigation of the evidence, that the natives of ancient Caledonia lagged far behind the other races of Northern Europe in the arts of civilisation--for their primitive arts precluded the construction of fleets fitted for the navigation of the intermediate seas, and shut them up to their own native ingenuity. Still it may be that the discovery of a more complete correspondence with the stone implements of other parts of Europe will yet add to our knowledge of the first colonisation of the British Isles, and help us to follow back the track of these nomadic tribes in their wanderings from the eastern cradle land of the human race.