193 



chaunels was suddenly arrested by the seismic distnrl)auees and the lava 

 flows of Post-Tertiary times. The former changed the incline of the river 

 channels, and the latter dammed up the rivers, thus forming lakes. In 

 these lakes were deposited the Pleistocene marls of the river valleys. At 

 the close of the Pleistocene, these lakes in turn were obliterated and the 

 country took on the general appearance that it has today. 



ECONOMICS. 



The altitude of this re;;ion. ."..(inu To U.om feet above the sea. and 

 the latitude thirty-tive to thirty-six degrees north, combine to give it 

 a climate which for mildness and equality has no superior in the world. 

 Its location, near the center of the vast rainless region of the West, and 

 its remoteness from .any large liody of water, give it an atmosphere al- 

 most totally devoid of moisture. At the .same time. l)y reason of the 

 latitude and altitude, the air is both warm and light, thus furnishing, in 

 unlimited nuantities. nature's sovereign remedy for all diseases of the 

 lungs. 



Soil.— The soil on the table lands, esiiccially on the Tertiary formations, 

 is poor. There is too much alkali, r.iit if the water for irrigating pur- 

 poses could be had. even the soil of these mesas, in a few years, could be 

 made prcdiu-tive. It would require considerable labor and the use of 

 fertilizers such as gypsum, liurned lime, etc., luiT in the end it would pay. 



On the mountain plateaus the soil is good, especially in the .lemez 

 Mountains in the Valle Orande country. This great valley, to interpret 

 the Mexican, occupies a high altitude, averaging O.OflO feet. "It embraces 

 KMj.tMJO acres, and forms fine prairies with abundant grasses. On it also 

 the fir and pine are most magnificently developed." 



In the valleys the soil is. without exception, the best in the world. It 

 surpasses evtn the soil of the Nile Valley. In speaking of the Rio Grande 

 mud. Dr. Loew. in the I'. S. (Geological Surveys of the Territories west of 

 the lOnth meridian (\"ol. 111., p. ."iT.S-.jS^i sjtys: 



"Irrigation with these mud-carrying waters furnishes the lands with 

 a layer of the best virgin soil in a finely pulverized condition, and the 

 belief of the farmer that the Rio Grande water is an efficacious fertilizing 

 agent is fully warranted by the facts re^•ealed by the chemical analysis. 



13— Aeatleiny of Science. 



