But we do not come to Dartmoor for traces of the earliest man in England; for these we must go to Kent's Cavern, Torquay, or to Brixham, not to the moors. Tokens of habitation on Dartmoor only begin with Neolithic times, and are by no means continuous. At one time there must have been a thick population; but Celt and Saxon have left little trace on the moors, and the Romans none at all. Though the Celts may have conquered the Iberian tribes here, they probably neither exterminated nor entirely dispossessed them. They were content with the fringes of the wilderness, leaving the rest to the mists, the wolves, and the lingering older race. It was man of the New Stone Age who first peopled this upland, leaving remains of his hut-dwellings, his pounds, dolmens, and menhirs, his kistvaens and his cooking-holes. Numerous as the remains are still, they were once far more so; they have been broken up or carted away for road-mending, for gateposts and threshold stones, for building, for "new-take" or other walls, and for any other purpose to which granite can be applied. This central highland may have become a refuge of the later Stone-men against invaders of better equipment: all the traces of camps are on the borders, defensive against an external enemy; within is no sign of anything but peaceful pastoral occupation and tin-streaming. Place names, of field or of farm, enable us to infer the former existence of primitive relics: wherever there is a Shilstone (shelf stone) or a Bradstone (broad stone) we may be sure there was once a dolmen or cromlech; wherever there is a Langstone or Longstone we guess at a menhir or standing-stone. These early inhabitants of the moor had advanced far from the condition of the rude cave folk; they built themselves low circular huts, generally clustered within pounds (enclosures whose chief purpose here seems to have been the protection of cattle; some of the pounds were clearly for cattle alone). At Grimspound, near Hookner Tor, are traces of twenty-four huts, enclosed in a double wall 1500 feet in circumference. The huts had low doorways, and usually platforms for domestic purposes, with hearthstones and cooking-holes. The food to be cooked was placed in the hole, sometimes in a coarse clay pot, sometimes without, together with red-hot stones from the hearth. Near Postbridge as many as fifteen pounds can be traced, while at Whit Tor are other numerous traces. Those at Grimspound evidently belong to the Bronze Age; like different periods of architecture, the Stone and Metal Ages very much overlapped.