The two Valleys.—The Lake with a leaky Bottom.—The Water could not have been higher.—Nor could the Lagunas or Ponds have been much deeper.—The Brigantines only flat-bottomed Boats.—The Causeway Canals fix the size of the Brigantines.—The Street Canals.—Stagnant Water unfit for Canals.—The probable Dimensions of the City Canals.—Difficulties of disproving a Fiction.—A Dike or Levee.—The Canal of Huehuetoca.—The Map of Cortéz.—Wise Provision of Providence.—The Fiction about the numerous Cities in and about the Lake.
It may be well here to repeat that, strictly speaking, there are two valleys of Mexico—the upper northern valley, and the valley of the city of Mexico; the first extends in an oval form to the north of the hills of Tepeyaca, some sixty miles, and communicates with the plains of Otumba and Apam. In this valley are the two ponds, or lagunas, of Zumpango and San Cristobal, the highest waters of Mexico; and in it also is the half of the Tezcuco, which is the lowest laguna of the valleys. It is a country of fine farming lands, and was probably inhabited long before the time of the arrival of the Aztecs in the lower valley, as I infer from its proximity to the extensive ruins of Teotihuican, that have come down from a remote and highly-civilized antiquity.
THE ANCIENT LAKES.
The valley of the city of Mexico, which lies to the south of these hills, is also of an oval shape, but is not more than twenty miles in extent. The surface-water with which it is saturated is in part fresh, and in other parts tequisquite; that is, where the waters have a current, they are fresh; but where they remain from year to year discharging their volume only by evaporation,