The only representative of this family is Xenosaurus grandis, recorded from the mountains of Orizaba, Cordoba and Oaxaca.
Similar rocks occur also in Chiapas, Oaxaca, Guerrero and elsewhere; but owing to the absence of any early fossiliferous deposits, the age of these rocks is very uncertain.
The first runs southward from the capital to Oaxaca through the rich sub-tropical states of Puebla and Oaxaca, and the other two run northward from the same point to the American frontier.
The " ni-in " (also known as " axe ") is a small scale insect belonging to the genus Coccus, found in Yucatan, Oaxaca, Vera Cruz, Michoacan and other southern states, where it inhabits the spondia trees and produces a greasy substance called " ni-inea," which is much used by the natives as a varnish, especially for domestic utensils, as it resists fire as well as water.
In 1906 the productive mines numbered 1786, of which 491 were in Sonora, 282 in Chihuahua, 211 in Durango, 113 in Oaxaca and 105 in Nuevo Leon.