seems that they were at one time very numerous, and many, no doubt, still exist which have escaped S. da Costa's enquiries. Neither he nor any one else appears to have visited Cape Cuneus, the most southern point of Portugal, where, if we read Strabo aright, dolmens certainly existed in his day;[1] and if they do so now, it would be a point gained in our investigation.
At present, according to S. da Costa, there are twenty-one dolmens in Alentejo, two in Estramadura, nine in Beira, four in Tras os Montes, and three in Minho. According to my information, they are numerous in Gallicia, but have never been described. Three at least are known by name in Santander, and as many in the Asturias. One at least is known in Biscay, and two in Vitoria; one in Navarre, and one in Catalonia. But I am assured that all along the roots of the mountains they are frequent, though no one has yet described or drawn them.[2] So far as is known, there are none in the Castiles, in the centre of Spain, and only that group above alluded to in Andalusia, where probably, instead of a dozen, it may turn out that there are twice or thrice that number.
Assuming this distribution of the Spanish dolmens to be correct—and I see no reason for doubting that it is so, in the main features at least—it is so remarkable that it affords a good opportunity for testing one of the principal theories put forward with regard to the migrations of the dolmen-building people. According to the theory of M. Bertrand, the dolmen people, after passing down the Baltic and leaving their monuments there, migrated to the British islands, and after a sojourn of some time again took to their ships and landed in France and Spain, to pass thence into Africa and disappear.[3] This seems so strange, that it is fortunate we have another hypothesis which assumes the probability of an indigenous population driven first to the hills and then into the ocean by the advancing tide of modern civilization.
The first hypothesis involves the assumption that the dolmen people possessed a navy capable of transplanting them and their families from shore to shore, and that they had a sufficient know-
