Besides these, however, there are tumuli at a place called Segewolde, and circles, sometimes with a stone in the centre, at Bajard, and no doubt other remains of the same class in the district. The purpose, however, of the only book I know on the subject was not to illustrate the forms of tombs, but that of the objects found in them, and to trace the ethnographic relations of the people who possessed them with the other tribes who at various times inhabited that district. The dates of the whole, according to their describer, may safely be included between the eighth and the twelfth century.[373] DRENTHE. The most southern group of these monuments belonging to the northern division is one of the most extensive, though unfortunately one of the least known. It is situated almost exclusively in the province of Drenthe, in North Holland, where the Hunebeds--giants' beds or graves, as they are locally called--are spread over an area extending some twenty miles north and south, and probably ten or twelve miles in the opposite direction. This tract of country is a bare open heath, which even now is only partially cultivated, or indeed capable of cultivation, and at no time could have supported a population at all in proportion to so extensive a group of monuments. As long ago as 1720, Keysler drew attention to them, and gave a representation of one in order to show its similarity to Stonehenge.[374] The engraving, however, is so defective that it is impossible to make out what it represents, and as no dimensions or statistics are given, it adds very little to our knowledge. A short paper on the subject appeared in the 'Journal of the Archæological Association' in 1870, but unfortunately without any illustrations,[375] and we are consequently dependent for our knowledge of them almost entirely to a work published at Utrecht in 1848, by the late Dr. Janssen, keeper of the antiquities in the museum at Leyden. This work is in many respects most painstaking and satisfactory; but, though it is hardly correct to say it, is without illustrations, the Hunebeds are represented by conventional symbols, which no one would guess were intended for buildings of any sort without a most careful study of the book. I have ventured to try to translate one of these into ordinary forms, in woodcut No. 120, but without at all guaranteeing its correctness. It is, however, sufficiently accurate to explain the general nature of the monuments.