“…This trend has usually promoted a significant concentration of manufacturing, both marketoriented and often also basic materials processing in the metropolitan region, because of its function as a transshipment node (Pred, 1966 ;Jefferson, 1939) . It has been noted, in connection with this trend, that long-term expansion of metropolitan per capita GNP in the early phases will most likely induce additional in-migration, infrastructural investment, and major changes in the intrametropolitan structure (Clark, 1967 ;Lave, 1970 ;Webber, 1979;Bergsman et al, 1972) . In developing nations, this process may last longer and can cross various metropolitan size thresholds before conditions more typical of the middle phases are reached .…”