Thus we find these early traders seeking for copper, tin and gold, or any other precious commodities, on the north-west of Europe before 2000 /B.C./, and it has been shown by various authorities that among the gold-fields explored at that time none was richer than the Irish gold-fields in the Wicklow Hills.[111] It is needless here to recapitulate all the evidence which has been adduced to establish the early working of these deposits. The wealth of gold ornaments of this period found in the island, most of which have passed into the melting pot, but hundreds of which are still in the National Museum at Dublin,[112] would alone be sufficient evidence; but we know also that certain ornaments, known as _lunulæ_ or crescents, were exported and reached Brittany, Denmark and Germany.[113] It is likely, too, that gold objects of Irish origin reached to more distant places.[114] This shows us that Ireland was in touch with the trade routes we have been discussing, and this in turn accounts for the vast numbers of bronze implements of early types which are to be found in all museums and private collections, not only in Ireland itself, but throughout Great Britain. It would seem probable that the early traders from the Mediterranean also reached the Baltic at about the same date, for we find there, too, an early bronze industry, which, while bearing a close resemblance to Central European models, exhibits also western and Mediterranean types.[115] The search for amber probably induced our traders to go to this distant region, for amber, like the precious metals, was much in request in Mediterranean lands, for again it was a substance from which beads could readily be made. It was probably these traders who carried with them the news of the Irish gold-fields, and in due course other traders, starting out from the Baltic, joined the gold rush. We have already seen that a gold crescent of Irish work has been found in Denmark, we can find, too, other evidence of this trade. Now if we plot out on a map of the British Isles the sites at which have been found the bronze implements of this period, and such a map of flat celts was published some years ago by Mr. O. G. S. Crawford,[116] we shall notice certain striking features. Where the chalk lands or limestone hills exist these finds are fairly numerous and generally distributed, for, as Crawford showed, these areas were open grass lands. But throughout the rest of the country these sites string out into long lines, and these lines, if produced, would intersect near Dublin; these lines seem to indicate trade routes, passing through thickly wooded and probably uninhabited country on their way to the Irish gold-fields.