marshes of Lake Tezcoco on the north, thence it passes over a causeway built across an arm of Tezcoco for two miles, and, by another causeway of seven miles finally strikes the city. The road is good, level, perfectly open and comfortable for ordinary travelling, but the narrow land between the lakes of Chalco and Tezcoco, compressed still more by broken hills and rocks, admits the most perfect military defence. At the end of the first causeway over the arm of Tezcoco which we have just described, is the abrupt oblong volcanic hill styled El Peñon, four hundred and fifty feet above the level of the lake, its top accessible in the direction of Ayotla at only one point, and surrounded by water except on the west towards Mexico. It is a natural fortress; yet Santa Anna had not neglected to add to its original strength, and to seize it as the eastern key of his defences. Three lines of works were thrown up, at the base, at the brow, and on the summit of the eminence. The works at the base, completely encircling El Peñon, consisted of a ditch fifteen feet wide, four and a half feet deep, and a parapet fifteen feet thick whose slope was raised eight and a half feet above the bottom of the ditch. Ample breastworks formed the other two lines of the bristling tiara. In addition to this, the causeway across the arm of Tezcoco, immediately in front, had been cut and was defended by a battery of two guns, while the fire from all the works, mounting about sixty pieces, swept the whole length of the causeway.
The second road to the capital was by Mexicalzingo. After leaving Ayotla the highway continues along the main post road for six or seven miles and then deflects southwardly towards the village of Santa Maria, whence it pursues its way westwardly towards Istapalapan, but, just before reaching Mexicalzingo, it crosses a marsh formed by the waters of Lake Xochimilco, on a causeway nearly a mile long. This approach, dangerous as it was by its natural impediments, was also protected by extensive field works which made it almost as perilous for assault as the Peñon.
The third route lay through Tezcoco. Leaving Chalco and the Hacienda of Buena Vista, it strikes off from the main route directly north, and passing through the town of Tezcoco, it sweeps west wardly around the shores of the lake of that name until it crosses the stone dyke of San Cristoval, near the lake and town of that name; thence, by a road leading almost directly south for fifteen miles, through the sacred town of Guadalupe Hidalgo, it enters the capital. It is an agreeable route through a beautiful country, yet extremely circuitous though free from all natural or artificial obstacles, until it reaches Santiago Zacualco within two miles of Guada-
