As wampum was made from marine shells,[8] it was naturally manufactured by the sea shore tribes, and in localities determined by the abundance of raw material. Here the shells were stored up in some convenient spot during summer, to be worked out in winter when the rigors of the season should deter the men from their ordinary out door pursuits.[9] Probably but little was produced north of the Narragansetts [Rhode Island], as the necessary shells were scarce beyond Cape Cod. The Narragansetts were themselves great producers, and tradition claimed for their tribe the honor of the invention of wampum. But the Long Island Indians were by far the greatest producers along our northern coast. Their sandy flats and marshes teemed with sea life, and, when the Dutch first came to New Amsterdam, their island went by the name of _sewan hacky_, or the "land of the sewan shell," so numerous were the sewan manufactories upon it. Without doubt production was stimulated beyond its natural limits by the demand from powerful tribes from the main land, who found it easier to exact wampum as tribute from their weak neighbors, than personally to engage in its laborious coinage. Hazard, in his collection of state papers, states, that the Narragansetts frequently compelled large tributes in wampum from the Long Island Indians. The Pequots also for many years prior to 1637, exacted large annual contributions from the same tribes while they were still further subject to the levies of the imperious Mohawks. Thus the mint of wealth at their very doors became to its possessors the source of untold misery. Constant fear kept them toiling at the mines, while the scanty proceeds of their labor only quickened the greed of their savage masters. The number and extent of the sewan manufactories upon Long Island may be inferred from the frequent and immense shell heaps left by the Indians in all of which scarcely a whole shell is to be found. Occasionally the whole shells were carried over to the main land and there wrought. From Sewan-Hacky down the Atlantic coast and along the gulf, the shaded covers and quiet banks were doubtless dotted with wampum manufactories, for there was a great demand constantly to be met. The inland tribes were of course unable to produce their own wampum, and depended for their supply upon the coast tribes. A brisk trade thus arose between the coast and interior. Hides and furs were brought down to clothe the denser population of the shore, and wampum carried back in exchange.[10] Often, however, the inland tribes were able to pounce down and wring this precious material from its carriers in the form of tribute.