KXPLANATION OF THE ILLUSTRATION 
Prare XXXVIIL. Photomicrographs of fossil, archeological 
and modern maize pollen grains. 
1, Belles Artes core sample number 163, slide number 5. 
Note pore at extreme upper right, and characteristic folds 
of the exine. 435 
2, Belles Artes core sample number 148, slide number 1. 
Pore is clearly visible in upper central portion of grain, >< 435 
3, Belles Artes core sample number 1638, slide number la. 
Pore is visible at lower right. The grain is nearly round, 
but deeply folded.» 435 
4, Bat Cave, New Mexico. Dated by radio-carbon age de- 
termination of associated charcoal at 5600+ years. Note 
large size of grain and conspicuous pore. » 485 
5, Bat Cave, New Mexico, Same source and age as grain 
shown in fig, 4.0» 435 
6, Thayer Flint, modern maize, for comparison with fossil 
maize pollen. Note conspicuous pore in central upper por- 
tion of figure, * 435 
