THE AZTECS 227 



In the cross-section of New World history presented 

 herewith the horizontal measures represent space and 

 the vertical measures represent time. The line A-B-C-D 

 begins at Victoria Island and ends at Cape Horn, 

 cutting across the culture areas named on the diagram. 

 Over a large part of this cross-section the " horizon of 

 recorded history"' is in fact the time of the first 

 European exploration, but in ( 'olombia and Peru, there 

 are well-defined traditions giving lists of kings, while in 

 Mexico and Central America there are exact chronol- 

 ogies going back about 2000 years at the maximum. 

 Below this and within it there are archseological records 

 of culture sequence which in some regions, such as the 

 Pueblo Area, have been nicely classified. On the basis of 

 trade relations and diffused ideas in material and 

 esthetic arts the marginal chronology can be tied in 

 with that of the central standard section of history. 



Of course, all dates earlier than the first recorded 

 ones are theoretical. The beginning of agriculture in 

 America is put at 4000 B.C. — it may be earlier, but can 

 hardly be much later when we consider the great depth 

 of the deposits of the Archaic Period. The first expan- 

 sion of agriculture was over arid lands with irrigation. 

 The second expansion came a long time later. The 

 Pueblo .Area (New Mexico. Arizona, etc.) received 

 agriculture on the first expansion while the Mound 

 Area doubtless received it on the second expansion. 



The dynamic forces in the history of man in the New 

 World have a tremendous bearing upon the present 

 and future state of the world. The debt which we 

 owe to the ancient civilizations of Mexico and Central 

 America becomes apparent when we list the more 

 Important agricultural plants, fibers, gums, dyes, etc., 

 which were taken over by Europeans from the American 

 Indian-. 



