Pearls, amber, coral, jet, &c., were searched for as well as metals. The megalithic monuments near pearling rivers, in the vicinity of Whitby, the main source of jet, and in Denmark and the Baltic area where amber was found were, in all likelihood, erected by people who had come under the spell of the same ancient culture.
When, therefore, we come to deal with groups of monuments in areas which were unsuitable for agriculture and unable to sustain large populations, a reasonable conclusion to draw is that precious metals, precious stones, or pearls were once found near them. The pearling beds may have been destroyed or greatly reduced in value,[69] or the metals may have been worked out, leaving but slight if any indication that they were ever _in situ_. Reference has been made to the traces left by ancient miners in Egypt where no gold is now found. In our own day rich gold fields in Australia and North America have been exhausted. It would be unreasonable for us to suppose that the same thing did not happen in our country, even although but slight traces of the precious metal can now be obtained in areas which were thoroughly explored by ancient miners.
[69] The Scottish pearling beds have suffered great injury in historic times. They are the property of the "Crown", and no one takes any interest in them except the "pearl poachers".
When early man reached Scotland in search of suitable districts in which to settle, he was not likely to be attracted by the barren or semi-barren areas in which nature grudged soil for cultivation, where pasture lands were poor and the coasts were lashed by great billows for the greater part of the year, and the tempests of winter and spring were particularly severe. Yet in such places as Carloway, fronting the Atlantic on the west coast of Lewis, and at Stennis in Orkney, across the dangerous Pentland Firth, are found the most imposing stone circles north of Stonehenge and Avebury. Traces of tin have been found in Lewis, and Orkney has yielded traces of lead, including silver-lead, copper and zinc, and has flint in glacial drift. Traces of tin have likewise been found on the mainlands of Ross-shire and Argyllshire, in various islands of the Hebrides and in Stirlingshire. The great Stonehenge circle is like the Callernish and Stennis circles situated in a semi-barren area, but it is an area where surface tin and gold were anciently obtained. One cannot help concluding that the early people, who populated the wastes of ancient Britain and erected megalithic monuments, were attracted by something more tangible than the charms of solitude and wild scenery. They searched for and found the things they required. If they found gold, it must be recognized that there was a psychological motive for the search for this precious metal. They valued gold, or whatever other metal they worked in bleak and isolated places, because they had learned to value it elsewhere.