The "Persian Gulf" types of circular, stamped (rather than rolled) seals known from Dilmun, that appear at Lothal in Gujarat, India, and Failaka, as well as in Mesopotamia, are convincing corroboration of the long-distance sea trade. What the commerce consisted of is less known: timber and precious woods, ivory, lapis lazuli, gold, and luxury goods such as carnelian and glazed stone beads, pearls from the Persian Gulf, shell and bone inlays, were among the goods sent to Mesopotamia in exchange for silver, tin, woolen textiles, olive oil and grains. Copper ingots from Oman and bitumen which occurred naturally in Mesopotamia may have been exchanged for cotton textiles and domestic fowl, major products of the Indus region that are not native to Mesopotamia. Instances of all of these trade goods have been found. The importance of this trade is shown by the fact that the weights and measures used at Dilmun were in fact identical to those used by the Indus, and were not those used in Southern Mesopotamia.