CHAPTER I. Geological and Geographical Structure of Mexico—Extent.

space between the northern extremity of New Mexico and Sonora, and the American boundary of 1819. Thirty-six thousand five hundred square leagues, comprising the States of Zacatecas, Guadalajara, Guanajuato, Michoacan, Mexico, Puebla, Vera Cruz, Oajaca, Tabasco, Yucatan, Chiapas, were within the torrid zone; while New Mexico, Durango, New and Old California, Sonora and a great part of the old Intendancy of San Luis Potosi, containing in all eighty-six thousand square leagues, were under the temperate zone.²

A more recent, and, generally, an accurate writer,³ has estimated the boundaries of Mexico, prior to the treaty of 1848, at Guadalupe, between the United States and Mexico, to have embraced an area of one million six hundred and fifty thousand square miles, including Texas. By the treaty just mentioned we acquired an undisputed title to Texas, and a territorial cession of New Mexico and Upper California.