ATLANTIC LOWLANDS OF MEXICO 121 



winds penetrate to the heart of the South Mexican mass 

 of mountains, the features of whose vegetation repeat, on 

 the whole, those just described : only the low plateau or 

 plain of Yucatan owes more to the porous nature of its 

 limestone than to its climate and displays a large develop- 

 ment of savana and jungle, while the hilly interior is 



FJG. 35. Dry scrub and cei'eus-trees on arid slopes. A small alluvial 

 cone, the abundant vegetation of which supports a group of huts 

 Tuland valley, Mexico. 



abundantly wooded up to the heath- or brush-clad table 

 tops. The inland and Pacific valleys are, by contrast, 

 very hot and dry, assuming frequently the character of 

 semi-deserts, with a scant vesture of acacia-scrubs or 

 wastes of cacti and succulents. 



The civilizations high enough according to all avail- 

 able records that preceded, and disappeared before, the 



