BOOK IV. 



CHAPTER I. 



Geological and Geographical Structure of Mexico — 



Extent. 



ABSENCE OF ACCURACY HUMBOLDT. SUPERFICIAL EXTENT OF 



MEXICAN TERRITORY. PHYSICAL STRUCTURE OF MEXICO 



VOLCANIC MOUNTAINS CLIMATES TIERRAS TEMPLADAS, CA- 



LIENTES j FRIAS. POLITICAL DIVISIONS AND BOUNDARIES OF 



MEXICO. OLD SPANISH DIVISIONS PROVINCES INTENDEN- 



CIES STATES DEPARTMENTS. NORTH BOUNDARY PRES- 

 ENT STATES AND TERRITORIES. RIVERS OF MEXICO. RIVERS 



AND LAKES OF MEXICO. 



It is unfortunate that, notwithstanding the rich mineralogical 

 and agricultural character of Mexico, no thoroughly accurate sur- 

 vey or geological examination has ever been made of the whole 

 country. There is no complete map of the territory which may be 

 confidently relied on. The enterprise of developing Mexico, since 

 the foundation of the colonial government by Spain has been almost 

 entirely abandoned to private enterprise, and, consequently the 

 valuable information, collected by individuals, either perished in 

 their hands after it had been used for their own benefit, or, if im- 

 parted to the government, has never been united and collated with 

 other accounts and reconnoissances which were in the hands of na- 

 tional authorities. A great deal was done by Baron Alexander 

 Humboldt, during his visit to New Spain early in this century, to- 

 wards gathering the geographical, geological and statistical infor- 

 mation which was then in existence, though scattered, far and 

 wide, over the viceroyalty, in a thousand different hands. His 

 voluminous work is an enduring monument to his industry and 

 talent; but there is necessarily a great deal of it that was altogether 

 transitory in its character both on account of the political and social 

 revolution which has since occurred, and in consequence of the 

 opening, by the republic, of Mexican ports to the commerce of the 

 world. 



Nevertheless, at the period of Humboldt's visit, the main bold 

 geographical and geological features of Mexico were sufficiently 

 well known for practical purposes, and as his descriptions have, in 



B 



