We are still, however, left in darkness about that part of the stone-age thought which has left the grandest traces, and of which we should so much have wished to be informed; I mean the religion. Besides the tumuli we have those enormous piles of stone called cromlechs, or dolmens, and sometimes _miscalled_ Druid circles--such as the well-known Stonehenge; these cromlechs were, we may believe, temples or sacred places. Each arrangement of the stones is generally like a simple portico, made by placing one enormous block upon two others; and these porticoes are sometimes arranged in circles, as at Stonehenge, sometimes in long colonnades, as at Carnac in Brittany. Lesser dolmens have been found in most European countries. There can be little doubt that these huge monuments possessed a religious character. And here is one proof of the fact. As a rule, the grave-mounds--the tumuli--are built upon elevations commanding a considerable prospect, and it is rare to find two within sight. Yet over Salisbury Plain, and the part about Stonehenge, they are much more numerous, as many as a hundred and fifty having been discovered in this neighbourhood, as though all the ground about this great cromlech were a hallowed region, and it were a desired privilege to be buried within such sacred precincts. Of the worship which these stone altars commemorate we know absolutely nothing. There seems to be no reasonable doubt that they belong to the period we are describing. The name Druid Circles, which has been sometimes given them, is an absurd anachronism, for, as we shall have occasion to see later on, the ancestors of the Kelts (or Celts), to whom the Druidical religion belonged, were probably at this time still living on the banks of the Oxus in Central Asia; at any rate they had not yet migrated to Brittany or to Great Britain. Thus, though we must continue to wonder how these people could ever have raised such enormous stones as altars of their religion, the nature of that religion itself is hidden from us. The tumuli and the relics which they contain are the truest representatives of the second stone age which have come down to us. The barrows raise their summits in every land, and the characteristic features of the remains found in them are the same for each. We must judge that they, that the most genuine stone-age tumuli, arose during the greatest extension of the stone-age races, before any new peoples had come to dispute their territory. What the kitchen-middens show in the germ, they show in its perfection--all the perfection attainable by it.