is an economic motive for inter-regional travel. Silvio Durante's study (1979) of marine shells from India and their appearance in the archaeological record in such distant sites as Tepe Yahya and Shahr-i-Sokhta in Iran, as well as in the Indus Valley, sheds light on the ancient trading routes of certain types of shells which are specifically and exclusively found along the Indian coastline proper. Durante primarily discusses the marine shell Xancus pyrum and the fact that it was traded whole and intact, then worked or reworked (into jewelry? sic) at its destination site, perhaps then moving on to other locations. The importance of this specific shell is that Xancus pyrum has a very limited geographic distribution and thus has almost the same significance in the field of shells as that of lapis lazuli in the context of mineral resources (as regards the determination of the possible routes along which a locally unavailable raw material is transported from a well-defined place of origin to the place where it is processed and, as also in the case of Xancus pyrum, consumed). Perhaps, as these shells crossed so many cultural hands, they were left unfinished in order for the final owner or consumer to work the raw material into a style and usage specific to their region. Durante offers four possible trade routes from their gathering zone along the west and northwest Indian coast to destinations west: sea route direct to the Iranian coastal area; sea route to Sutkagen-dor and Sotka-koh on the Makran coast, then overland westwards; overland through the Indus plain and then through the Makran interior to Sistan; overland through the Indus Valley and then through the Gomal Valley to Sistan." See also List of Indus Valley Civilization sites Sutkagan Dor Indus Valley Civilization Lothal References External links The Indus Valley Civilization: In Search of Those Elusive Centers and Peripheries Explorations on the Makran Coast, Pakistan: a Search for Paradise by Dales and Lipo, 1992 (Full text) The Demise of Utopia: Contexts of Civilizational Collapse in the Bronze Age Indus Valley Harrapa and Indus Valley Civilisation at harrapa.com Moenjo-Daro: A 5,000 Year Old Legacy Archaeological sites in Balochistan, Pakistan Former populated places in Pakistan Ghost towns in Pakistan Indus Valley civilisation sites Geography of Balochistan, Pakistan