HIGHWAYS LAKES ZUMPANGO CBJSTOVAL. 235 



Its greatest length, from the mouth of the stream of Tenango in 

 the lake of Chalco, to the foot of the Cerro de Sin6c, in the neigh- 

 borhood of the canal Huehuetoca is 19|- leagues, and its greatest 

 breadth, from San Gabriel at Tezcoco, to the sources of the river 

 Acapusalco at Quisquiluca, is 13^ leagues. Its area is 258f square 

 leagues, 23^ of which are covered by lakes. On the south, east, 

 and west, the mountains maintain a probable average height of 

 10,000 feet above the sea, while at the north their depression is 

 considerable, and through the gaps and vallies the waters of the 

 lakes are discharged towards the Gulf of Mexico. 



Six great highways centre in the capital, and leave it to traverse 

 the principal districts of the confederacy. 



1st. The road to Acapulco on the west coast, which passes out 

 of the valley over its southern rim of mountains at the point known 

 as the Cruz del Marquez, about 2,284 feet above the city of Mex- 

 ico, or 9,784 above the level of the sea. 



2d. The road to Toluca, by Tianguillo and Lerma. 



3d The road to Queretaro, Durango, &c. called El Camino de 

 tierra adentro, which leads across the eminences at the north of the 

 valley, by an elevation of about 100 feet only above the level of the 

 lakes. This road is the highway for the internal trade of Mexico 

 with the northern provinces. 



4th. The road to Pachuca and Real del Monte in the mining 

 district, across the Cerro Ventoso. 



5th. The road to Puebla, across Bonaventura and the plains of 

 Apam. 



6th. The new road to Puebla and Vera Cruz, by Rio Frio and 

 San Martin, across the northern shoulder of the volcano of Popoca- 

 tepetl. It greatest elevation is at the barranca or ravine of Juanes, 

 10,486 feet above the level of the sea. Besides the two last 

 mentioned roads there is a third, between the volcanoes of Popoca- 

 tepetl and Iztaccihuatl, by Tlamanalco, Ameca, La Cumbre, and 

 Cruz del Correo, passing out of the valley of Mexico into those of 

 Cholula and Puebla. 



Five lakes are embosomed in the valley in the immediate neigh- 

 borhood of Mexico: — 



1st. The lake of Zumpango, is the northernmost, and has an area 

 of about 1| square leagues. A dam, called La Calzada de la Cruz del 

 Rey, divides it into two basins, the westernmost of which is known 

 as the Laguna de Zilaltepec, and the easternmost, the Laguna de 

 Coyotepec. It is 26 feet higher than the mean level of the lake of 



