RIVER FRONT OF TAMPICO, MEXICO 



Photo by Frank M. Chapman 



treatment ; a rubber planter went south 

 to the Isthmus, an oil-man north to the 

 petroleum deposits near Tuxpam, and an 

 archeologist left for the ruins on the 

 table-land. 



Some came to buy, others to sell, and 

 in more settled lands we might have had 

 small interest in them or their calling, 

 but your commercial man in the tropics 

 is often an adventurer at heart and an 

 explorer in practice, and if his reports to 

 his "house" never reach the pages of a 

 geographic magazine, we may admit that 

 they not infrequently contain more novel 

 information than many reports that do. 

 Gratefully do I acknowledge my debt to 

 these Knights of Trade, whose intimate 

 knowledge of little-known trails and 

 places has been of no small value in solv- 

 ing problems of transportation and sub- 

 sistence. 



WE PASS THROUGH TROPICA!^ TEMPERATE, 

 AND BOREAT ZONES IN 75 MIEES 



My own mission in Mexico was to 

 make field studies and collect specimens 

 and accessories for an American Mu- 

 seum Habitat Group, designed to illus- 

 trate the effect of altitude on the distri- 

 bution of life ; and the fact that nowhere 

 on the American hemisphere can this be 



done so effectively as in the country lying 

 between sea-level and snow-line on Mt. 

 Orizaba, is in direct support of the claims 

 made for the diverse interests of this 

 truly wonderful region. 



Reference to a map of the natural life 

 areas of North America shows the tropic 

 region stretching up two narrow arms on 

 the Gulf and Pacific coasts of Mexico 

 which, in places on the higher Sierras, 

 are paralleled by southern extensions of 

 the 'Canadian Zone of the north. Be- 

 tween the two lie bands of the Temper- 

 ate Zone. 



Thus, in our journey from the Gulf 

 to the summit of the Sierra, we pass 

 through Tropical, Temperate, and Boreal 

 zones — the Tierras Caliente, Templada, 

 and Fria, of the native. Our actual jour- 

 ney, in passing from sea-level to snow- 

 line, may be a matter of 75 miles, our 

 change of altitude approximately three 

 miles ; but if we were to seek the Cana- 

 dian Zone not on mountain top but on 

 the coast, it would be necessary for us to 

 travel to Maine or Nova Scotia. In other 

 words, a journey of some 1,500 miles 

 would be required to reach conditions 

 which are here distant but three altitu- 

 dinal miles. 



536 



