The nephrite and jadeite of the lake-dwellings were long supposed to be imports from eastern Asia--until it was discovered that the material of many of those implements differed in microscopic structure from the Asiatic, and then were supposed to be of indigenous material. Probably both extreme views are untenable. A certain amount of communication with the Orient is shown by the occurrence of rings made of recent shells of Tridacna or Spondylus in Egypt, throughout the Mediterranean region, in France, and occasionally in middle Europe. The material apparently came from the Red Sea or the Indian Ocean. The same is true of a shell of Meleagrinia found in a hut-foundation in Rivatella, Italy.[114] Ornaments in the form of Mediterranean shells strung as necklaces are not uncommon in France, and occur elsewhere. The Mediterranean lands were in close communication with Egypt and Asia Minor; Spain with Africa, which furnished ivory and carved ostrich egg-shells carried farther north in rare instances. Stone palettes similar to those found in Egyptian graves occur in southern France and elsewhere. More careful search and study will doubtless greatly increase the number of similar illustrations. Scandinavia was already showing its appreciation of beauty of form and finish, which made its products unsurpassed during the Bronze period. Its marvellous flint daggers and hammer-axes were widely distributed and excite our admiration to-day. But the product which it was later to export to Greece and Italy in payment for the metal and art-treasures of the south was amber, an admirable material for jewelry, easily cut, transparent, of various hues, and taking a brilliant polish. So Homer speaks of a royal necklace, "golden, adorned with amber, like a blazing sun." Far back in Neolithic times we find jars containing large quantities of amber in the form of rude beads. One such hoard contained 4,000 articles, and weighed 17 pounds. The amber was evidently used for necklaces, and was common in the graves of the earlier epochs. It seems to have made its way slowly over North Germany. Amber beads occur very sparingly in the lake-dwellings. During the Bronze period it disappears largely in Scandinavian graves and is here less used for ornaments, but appears in Greece and Italy, where its beauty and possibilities could be properly appreciated. The value of amber in Scandinavia as an article of export rose to such an extent that the inhabitants largely gave up the use of it and exchanged it wholesale for the more attractive and useful metal. During this period there was a regular trade-route between the Baltic and the Mediterranean. [Illustration: BOATS FROM ROCK CARVINGS IN BOHUSLAN, SWEDEN. (EARLY BRONZE AGE)]