Photograph by O. F. Cook 

 ANOTHER ILLUSTRATION TO SHOW THAT THE SOU, AND SUBSOIL OF THE TERRACES 

 WERE PLACED AS LABORIOUSLY AND CAREEULLY AS THE WALL ITSELF 



The structure of a large agricultural terrace exposed along the stream near the middle 

 of the valley, seen in the photograph on page 506, shows that these broad terraces are as truly 

 artificial as the narrow ones on the slopes. A part of the old retaining wall that protected 

 the terrace from the stream is still in place at the right, while the naked bank at the left has 

 the same arrangement of fine soil above and loose stones for subsoil as the narrow terraces 

 of the hanging gardens (see text, page 496). 



tried, because of our lack of information 

 regarding the normal behavior of the 

 plant and the natural conditions to which 

 it is adapted. As might have been ex- 

 pected, if these facts had been known, the 

 best results thus far obtained from the 

 Cuzco corn in the United States have 

 been in California, in the cool climate of 

 the coast districts, where there is too little 

 heat for our eastern varieties to thrive. 



Thus the first step in determining the 

 possibilities of acclimatizing and adapting 

 South American varieties of corn to use 

 in the United States is to place them 

 under conditions where the plants can 

 behave in a normal manner and mature 

 seed. In experiments conducted last year 

 near the coast of southern California all 

 of the varieties from Peru and other 

 table-land regions of tropical America 

 were able to mature seeds, which many 



of them had failed to do when planted in 

 the Eastern and Southern States. 



A CORN THAT GROWS AT AN ELEVATION 

 OF 13,000 FKET 



The cultivation of corn in a cool cli- 

 mate has been pushed to an extreme limit 

 on the high plateaus around Lake Titi- 

 caca, where a dwarf form of corn is 

 planted at an elevation of nearly 13,000 

 feet. The specialized nature of this va- 

 riety became apparent in the experiments 

 near San Diego, where it matured in less 

 time than any other, or in about 60 days. 

 Worthless as it would appear from the 

 insignificant nubbins that we purchased 

 from the Indian women in the market of 

 Copacabana (page 523), this dwarf table- 

 land form is distinctly of interest as an 

 example of a variety with much lower 

 heat requirements than those we now 



S09 



