Glass trade bead assemblages recovered during archaeological investigations at nine sites by Smithsonian archaeologists Betty Meggers and Clifford Evans in Brazil in 1948 and 1949 and Guyana in 1952 and 1953 date to multiple time periods, including the early 17th, mid-18th, mid-19th, and mid-20th centuries. The assemblages are used to show that the glass bead chronologies developed in North America are directly applicable to South America and that there is a global glass bead sequence related to European colonialism. White drawn glass beads were independently dated by comparison with known composition changes through time in how the glass was made opaque. Compositions were determined using pXRF.
