Page
11 USGS
12 USGS
14, 16, 17 Willard F. Libby
18 University of Arizona
21 Massachusetts Institute of Technology
22 Graduate Research Center of the Southwest
23 Graduate Research Center of the Southwest
25 Robert L. Fleischer
26 Perkin-Elmer Corporation
30 University of Texas
32 Graduate Research Center of the Southwest
36 Massachusetts Institute of Technology
40 Des Bartlett, Armand Denis Productions
43 Anthropology Department, SMU
44 USGS
47 USGS
59 Author’s photo courtesy Graduate Research Center of the
Southwest